Tweets from 2020

Just remembered something - at #BigMathsJam, who asked me about my droste Dobble set?

@icecolbeveridge Take your like and get out

@KESMathematics HOW MANY YEARS AGO???

Ed Pegg, Jr has started updating mathpuzzle.com again! Hooray!

@sxpmaths Yeah, those are great!

🧓 "That's a nice dress, (2-year-old)"

👶 "IT'S GOT POCKETS!!!"

#StartYoung

I think this hyperbolic tiling I left in my last office might be ten years old!

@Andrew_Taylor "I would've got away with HS2 if it wasn't for you pesky kids!"

Oh no, I've written 'except' six times and it's now an unpronounceable mess of letters

@honeypisquared do you know of a decent taxonomy of mathematical topics, covering as wide a range as possible but particularly secondary and HE? At the moment I'm using the mathcentre taxonomy (mathcentre.ac.uk/types/communit…) which is old and missing lots of things

@honeypisquared I want a set of categories to describe what ideas a question assesses. The mathcentre taxonomy is a hierarchical thing with entries like "Numbers and Computation -> Arithmetic -> Operations -> Multiplication".
I don't think a hierarchy is correct, but (1/2)

@honeypisquared I want someone else to have thought about all the concepts involved in maths at the level I'm working in, and how they relate to each other, so I can have a standard way for question authors to say "this question is about factorising quadratics" without making up their own tags

@Kit_Yates_Maths @GermanQuatsch might get it?

Is my daughter too young for NP-hard problems?

@Simon_Gregg It's a poncey toiletries advent calendar

@Simon_Gregg Oh, it's the twelve days of Christmas. That hadn't twigged in my head

@ncllibsage 1906?

@MouldS Maybe @colourblindorg?

The phishing is coming from _inside_ the social network!

@NewcastleUniUCU @UniofNewcastle Known knowns - that's knowledge squared

I can't work out what WolframAlpha is doing wrong with this query: wolframalpha.com/input/?i=deriv…"derivative of (vector{1,2} dot vector{x,x^2}) with respect to x"

It can do the dot product properly on its own: wolframalpha.com/input/?i=vecto…

@d_yellowlees I hit deleted items 420 yesterday.

Is anyone planning anything for the next palindrome day, 2020-02-02?

@letsgetmathing I think that means it's a feast day for you

@honeypisquared @AlxHague 70

Yes!!! twitter.com/breenmij/statu…

@MathsInspiratn @StatsJen @hughhunt @tomrocksmaths Will any of you have time for a drink?

Recipe for instant mathematical delight: search MathWorld for the word "surprisingly"
mathworld.wolfram.com/search/?query=…

Is this @My_Metro stat misleading? Does "escalators were working" mean:
- every escalator was working
- every station had a working escalator
- every station had working escalators in both directions
- they measured time each escalator was running, and took the mean

The first two options are straight out, because one of the escalators at Haymarket has been broken for weeks. And if it's the mean, should it be weighted by usage?

@Smylers2 That's the most pessimistic option, which I didn't even want to think about

@tomrocksmaths @SamHartburn @StEdmundHall @UniofOxford Sounds fun!
Format feels familiar...

Uh oh.

It's 95% all the way down.

(95% of the way down)

Writing a follow-up to "How to Lie with Statistics", titled

"The Enormous Difficulty of Telling the Truth with Statistics"

@RAnachro Some people say 'percentage points' to make that distinction. E.g. if 20 if 100 people were ill and now it's 30, that's an increase of 100 percent or 10 percentage points

@SamHartburn to make the graphic work. I don't have a problem with it

Does *your* calculator give the numbers happy little emoji names?
Mine does.
somethingorotherwhatever.com/nice-calculator

Dredging through @aperiodical's comment moderation backlog, I spotted this interesting app by @NathanFallet: delta-math-helper.com
Looks like it'd be useful if you have a few calculations that you need to over and over

@Shona_Mu Someone should tell the conference I spoke at, where I had to submit an actual 8-page paper to go with my talk. Not sure the paper was ever published anywhere

Cor golly, ten years today since I wrote my first maths blog post: checkmyworking.com/2010/02/whats-…
In the ten years since then, I've narrowed down my interests from "all maths" to "all maths except pregroups"

@ben_nuttall But Choco Liebniz is right there.

@matheknitician @WoollyBenguin My grandad was one of the first dialysis patients and held the record for longest time on dialysis. I'm glad someone donated theirs to keep you going

@matheknitician @WoollyBenguin No, London. Don't tell anyone, but I have Southern roots

@JimPropp Yes: I wrote a parser for asciimath syntax, and it has an open bug from someone who encountered just such an ambiguity. It involved normal parentheses too, somehow

@honeypisquared "Playing With Infinity", written by Rózsa Péter while confined to a Jewish ghetto during the war, is as good a pop maths book as any.

@honeypisquared @AlexandraBerke's Beautiful Symmetries is a worthy contribution to the genre beautifulsymmetry.onl

@kyledevans @TLMaths oh my god. Please say he got a computer to generate these

Currently embroiled in an all-Chris email conversation. Have had to resort to using surnames to have any chance of knowing who we're talking about

#Diversity

@stecks @mscroggs @aPaulTaylor I know which way it was for my puzzles

@KentHaines Not sure I have something ready-made, but you could ask "does doing <operation> to both sides of an equation always/sometimes/never preserve the equation?"

Maths modelling exercise: describe the shape of this pack of butter as it's used up

@GwoMaths @MathsTim What's a nickel worth, and what's a dime worth?
Yours,
Confused of Great Britain

@icecolbeveridge Presumptuously, Austin sat down before the dinner gong was sounded

@icecolbeveridge Alright:

Ever since his rambling speech, Mr Romney was intermittently asked "But why do you want to be buried under _that_ ward?"

@FOTSN are you telling me you haven't watched the Clangers with the subtitles on?

@FOTSN oh no, cooler heads have prevailed on series 3. What a bore!

Series 1 was like this:

@becky_k_warren @DavidKButlerUoA There's a really good French word for people like this: 'yakafokon' (just do... /you just have to...) fr.m.wiktionary.org/wiki/yakafokon
V satisfying to shout when annoyed.
Mrs L-P has also banned "it should work" for similar reasons.

I'm not sure I've seen this puzzle before, and I really like it:

We have n keys and n boxes. Each key fits only one box. We shuffle the keys and put one in each box. Then we randomly break open 1≤k≤n boxes. What is the probability that we can unlock all the other boxes?

I'm trying to see if I can turn this into an intuition-challenging result, like the birthday paradox.

"100 boxes, I open 99 of them, prob you can open the last one?" (really high, not surprising)

"100 boxes, I open 1, prob you can open all the rest?" (higher than you'd think?)

The birthday paradox works as a demo because you can engineer an astonishingly high probability from what looks like a small part of the probability space.

Maybe this is the one probability puzzle that *does* match our intuitions.

@PetersenGraph that's certainly true!

@victorolosaurus @stevenstrogatz A key can be in the box that it unlocks. If you're worried about that happens practically, maybe a box snaps locked when you push its lid down.

I've been thinking about the fact that an n×n square grid has as many cells as a triangular lattice with n triangles on each side.
Is there a nice continuous bijection between them? When n is odd, you can at least keep one line of symmetry throughout.

Here's the same thing for a 2×2 grid. The triangle in the middle has to go one way or the other, so you have to break the vertical line of symmetry

I've made a nice looping thing!
triangle-square.glitch.me

@ColinTheMathmo open k boxes first

@BarbaraFantechi ah, like this!

@Pecnut @stecks getting that on a t-shirt post-haste

@SamDurbin1 @stecks Conversely, I maintain there's no way to get a gang of unruly year 10s on board like a rude-sounding name and a rude-looking diagram.

@BarbaraFantechi currently negotiating getting some time set aside at work to do arty stuff, so: soon!

@MathsInspiratn That'd be lovely. Would you like different colours, or a black background?

@mrtheta33 Yes

@robeastaway or, since months are cyclical, shift everything right by three months. That's easier to visualise

@ZoeLGriffiths @robeastaway I was surprised Feb 29th was higher than those. You'd expect four times as many on the 28th as the 29th, but apparently not!

@robeastaway @ZoeLGriffiths ah!

Thanks to tips from a couple of people, I've done some more work on what I'm calling the squiangle.

@icecolbeveridge @SamHartburn @Trianglemancsd random-people.glitch.me

Oh, to have the confidence of a man explaining prime-finding algorithms to Simon Plouffe

@SamHartburn @icecolbeveridge Absolutely!

@SamHartburn Yep, that's right. And tell me, because I could use data from other countries!

New #MathArt on display in @NCLMathsStats. Based on my 'squiangle' triangle → square transformation.
This piece shows the sequence of moves triangle → square → 90° rotation → triangle → 120° rotation

@NCLMathsStats You can see that transformation in motion at squiangle.glitch.me

@Ayliean @NCLMathsStats Hmmm! 🤔

Were you expecting this?

This is an incredible integer sequence: oeis.org/A000201

@roger_mansuy the Jessica Stockholder sculpture at IHES is what inspired me to find that sequence :)

@robinhouston @theoremoftheday I got to it via the "if n is in the sequence then n+(rank of n) is not in the sequence" definition. I was very surprised to find the fibonacci word!

@OpenLab_Ncl do you know if there are any laser cutters on campus that I (a staff member) could use?

@jjaron *gasps in Northern*

I know what I'm doing this morning oeis.org/A093579

I am not a lecturer. I am on strike. I'm on strike both for my own pension, and for others who have it worse than me, due to insecure employment or inequitable opportunity. twitter.com/pipmcgowan/sta…

This is your semi-regular reminder that the thaMographe exists, is easy to use, and less hassle to keep in your bag than a set of compasses, protractor and ruler. twitter.com/thamographe/st…

@jjsanderson A glitch in the matrix

Nominative determinism and Tyson Fury:

@NewcastleUniUCU @Athena_SWAN My favourite thing about the uni's EDI events is how many of them are outside core hours...

My daughter calls 10 'one-zero' and, honestly, she's got a point

@acubley A perfectly cromulent number

@mikegibson2010 I think I'd go 'f twice'

@rooneyvision @thetrainline Is it bad that I recognise the film that's from?

@rooneyvision @thetrainline this one from 1948, about UCLA's mechanical computer vimeo.com/70589461

@honeypisquared Happy bday!

@haggismaths @stecks @peterrowlett @aperiodical @NewtonInstitute Peanocast: each episode is about the previous episode

Best use of the Bercow gif, 2020 twitter.com/EnDirectDuLabo…

@blatherwick_sam I'd never been bothered before about whether 100 had to be a square number

I'm a big fan of whatever this is mateturismo.wordpress.com/2020/01/30/cha…

When we say 'time is a dimension', this is what that means. twitter.com/JanWillemTulp/…

@RrrichardZach I had to look at the source of kpathsea recently, and I just shook my head and closed the editor

@SLSingh a similar site in English is numdic.com

As the song goes:

🎶 Blue and yellow and that is all,
Yellow and blue and that's it.
I can see both colours
Of the rainbow,
There are only two. 🎶 twitter.com/DrJeniMillard/…

My first thought, 'Sleuth Women', was stronger, but I'd have had to recuse myself

I need you all to know that our team name at the murder mystery yesterday was "We've got a Maigraine" and I think the organiser thought I'd just misspelt 'migraine'.
Anyway, the prize for best name went to 'Giggle girls', so it was clearly a fix.

@AnonMathMom We've had the same - noticed all four molars last night. After the nightmare of the other teeth, this feels like an anticlimax

@MathsTechnology @TMiPUK @MathsWorldUK Up north *would* be good!

Not sure how I feel about this.

Or this.

@GhostMutt In JavaScript, render each frame to a png file using the node 'canvas' module, then use ffmpeg to make them into a movie.
The code is online at github.com/christianp/ani…

Slightly favourable about this

Whoosh!

@yenergy Have you seen Miss Fisher's Murder Mysteries? Extremely low-peril and camp detective drama

Kaboing

A day's break in the strike has allowed @Tegglington to open-source Coursebuilder, the tool we made to produce accessible web-based versions of lecture notes.
github.com/coursebuilder-…
It takes in LaTeX, and outputs HTML pages and slideshows.

@Tegglington There's a load of related stuff around automatically building notes and providing access to them through the VLE, which we'll also open source later, but we thought it was important to get the main part of the tool out, for those who can use it.

Triangular!

Inspired by the recent fuss about who Michael Bloomberg could give $1 million to, I've made a thing on @glitch which asks for your net worth then tells you where in the USA you could give everyone $1 million (or $1, or $100, or ...)
make-it-rain-bloomberg.glitch.me

@glitch I've written a bit about it on @aperiodical: aperiodical.com/2020/03/where-…

@anildash @glitch Oh yes, good point! Will do.

@anildash @glitch Although what that would look like on phones needs some thought

@ColinTheMathmo @neil_calkin Colin, the only conclusion that makes any sense is that you wronged a computer at some point in the past and it put a hex on you

@alexandersafir @anildash @glitch They are

@joelbezaire @mathhombre It looks like part of the way towards peasant multiplication: en.m.wikipedia.org/wiki/Ancient_E…

@DavidKButlerUoA Wikipedia says 9 is an 'absorbing element' en.m.wikipedia.org/wiki/Absorbing…
But I'd always call it a 'zero element'.

@DavidKButlerUoA But ZERO IS SO COOL

@DavidKButlerUoA Just spotted I wrote 9 instead of 0 🙄

@DavidKButlerUoA What do we call the coolest thing possible? ABSOLUTE ZERO. Quod Erat Demonstrandum, CP out

@lyd_w How is it only day 10?! I've forgotten what my job is

@lyd_w

@uncanny_static I camel-case the title. I don't do a lot of scholarly writing, so this scheme might not be tenable for anyone else

Well done to whoever on the @NewcastleUniUCU #UCUStrike made this placard!

How does Richard K. Guy not have a MacTutor biography?!

@mikegibson2010 @oganikathegames Did I see an early version of this a year or two ago? It feels familiar

@CardColm John Conway has one.

@RobJLow @ColinTheMathmo Yeah, I can't think many English mathematicians of the 19th century had PhDs

Clonk

Ah! That's how you do it!

Who called it a magma and not a hemidemisemigroup?

@siwelwerd @katemath @impredicativity @maryepilgrim @Oreo You have not lived.

Colleague sending follow-up emails to ask why I haven't responded, as if he's completely unaware of the #UCUStrike 🤷‍♂️

Kerchonk

I've made a t-shirt out of my squiangle design. Here's what it looks like on algorithmically-generated hunk Chad McYank redbubble.com/shop/p/4574510…

I've just found out there's an episode of Postman Pat about change-ringing bbc.co.uk/cbeebies/shows…

2020 and the Cambridge journals website still has the link to read the PDF behind an obscure icon next to the sharing links.

@honeypisquared *consults Cluedo board*

I'll be in the... ballroom

(quietly assuming that the people who keep the server farms running are still going in to work)

@peterrowlett I am so ready to talk with your son about this kind of algebra!

@peterrowlett Yeess, yeeeesss, feel the call of the dark arithmetic!

@JanvierUK I mean, it'll put people off knocking on your door, so in a way, yes

There is a Microsoft Teams app for Linux. What a crazy world.

The person doing the Abel prize announcement appears to have chosen as his green screen background "unregulated hotel room"

I want as many different conventions for writing numbers as you can give me. I'm interested in contexts where there are different rules for how numbers are written, e.g. scientific notation, percentages, currencies.
I'm also interested in 'optional' things like grouping digits

Which numbers can you represent with different notations? For example, decimals represent numbers of the form a×10ᵇ, so not even all of ℚ!
What fruity sets can we find a corresponding notation for?

@semiBad that's a brilliantly lateral way of finding some! I've looked at the source code for a few internationalisation formatters though, so cut out the middleman

I've seen gas stations in the US show the tenths part with a fraction instead of a decimal.
Have you seen any other signage with a fixed denominator that isn't 10?

Or, more thrillingly, are there contexts where numbers are written as decimals, but some decimals are illegal?
This is sometimes true for currencies: a price like £1.054 would normally be rounded to the nearest penny. But if it's a price per unit, you might need that extra digit

@LearningMaths that's exactly what I'm looking for! Thanks!

@miclugo that rings a faint bell! Thanks!

@UD_engr88 thanks! Do you know roughly when it changed?

@DavidKButlerUoA @LearningMaths ahh, I knew I'd seen that kind of thing recently! Thanks

I've just seen that @mickaellaunay is doing daily fun maths livestreams: youtube.com/watch?v=J6tcnc…

Is anyone doing something similar in English?

@boss_maths @UD_engr88 yess, this is the kind of knowledge I need!

Percentages highlight an often-ignored point about rounding: if you've got a boundary, rounding to it can be very misleading.
For example, if something works 999 of 1000 times, it's not correct to say it's 100% effective. 99% is further from the true value, but shows the failure.

@jonpenguin oh, that's new to me. Thanks!

@oscarwlog Yes, that's a good vein of odd notation. Have you seen fractional numbers in hex or octal notation? I've definitely seen binary fractions, but can't think where I might have seen a fractional hex value

@CPANJGamble ... how did that help?

@poveryant As in 3,300? That's new to me, thanks

@EmJayLambert @icecolbeveridge That intrigued me greatly, but this page - metricviews.org.uk/2012/05/fire-h… - says the top number is the size of the mains, and the bottom is the distance to it, so it's just a scalar

@icecolbeveridge @TeaKayB @samholloway @theclairodactyl @SamHartburn

@bbarber_ Could you do it online?

Slowly becoming more and more annoyed that the android and web-based versions of @msonenote don't have the "insert space" tool.

#WorkingFromHome

#NoPlagueToday

@algorithmachine @katemath @AndrewR_Physics @pa28 @ChrisMihos 85 is unimaginably hot to me. I'm on your kids' side

@dennisprangle Are you in the MSP online teaching group on Teams? We've been looking into that

@k_houston_math @_jcken @stecks It's very good for self-service formative use, and doesn't need anything installed to use. We're doing all sorts to support online teaching here, but early next week I should have a simple LTI solution which doesn't need installation but allows reporting score back to your VLE

@k_houston_math @_jcken @stecks VLEs with built in SCORM players such as Moodle and Blackboard (but BB is full of bugs) can also put scores from Numbas directly into their grade books without any software setup.

@k_houston_math @_jcken @stecks On the subject of exams: we're still thinking this through ourselves. Exams could happen in Numbas, but because everything has to be auto-marked, you're a bit limited in what you can ask. Randomisation reduces the efficiency of copying answers, though.

@k_houston_math @_jcken @stecks You can set questions creatively to test student understanding of concepts, but you can't ask for a proof. So, good for things like service courses and applied subjects, but less so for pure maths

@k_houston_math @_jcken @stecks One feature of Numbas' design will come in very handy: it runs entirely on the client, so not affected by poor Internet connections when submitting answers or rendering maths.

@k_houston_math @_jcken @stecks No problem, go ahead!

@poveryant So the games like NBA 2K3 conflict with that

@honeypisquared @asharpeducator And here's me with my own stupid name as a username!

@BiCapitalize Would you say you are rouxful?

@k_houston_math I'm not sure that's the kind of thing we'd ever be allowed to share. Might get away with a question from a mock, when they exist

@ColinTheMathmo PeerTube?

Tech support email: "We encountered many errors while following the instructions published at <address>. Do you have a version without errors?"

Just.... what.

What forethought of @peterrowlett and @stecks to round up and interview the makers of every maths podcast going, just before we all got locked down. twitter.com/aperiodical/st…

@statto I've been meaning to ask if network theory can tell me either:
- how many of the people I know should I expect to be infected, or
- given how many people I know are infected, can I estimate the population infection rate?

Not since GDPR day have I been made aware of so many mailing lists that I didn't ask to be on.
No, hotel I went to 9 years ago for afternoon tea, I don't want to know what you're doing about coronavirus.

@BassMonkey_ @glitch @standupmaths I think that might be @glitch doing some maintenance. Surely even Matt can't send enough traffic to cause them trouble?

@BassMonkey_ @glitch @standupmaths ah, the status page says they're deploying a fix: status.glitch.com

@GhostMutt More tins of veg means either 2 or 3 veg.
Prob(3 veg) is easy, because there's only one way of doing it: 5/9 * 4/8 * 3/7.
Prob(2 veg) is a bit harder: either VVT, VTV, or TVV. So 3*(5/9 * 4/8 * 3/7)
Add those together to get total prob

@GhostMutt You could work out the probs for VVT, VTV, and TVV separately, but it works out the same (try proving that!)

PS: what system is that?

@GhostMutt A rule of thumb is: if you write more than a page of working for one calculation, consider looking for a one-liner

Liven up lock-down: it's not social distancing, it's Covid Ops.

Sneak in and out of the park without being seen by another soul. Erase all trace of your activities with thorough hand-washing.

I promise I didn't plan this

Is it 'lockdown' or 'lock-down'?

A few years ago, we paid a web developer to make a website for us. The HTML uses single quotes for attributes, and is double-spaced throughout - there are two linebreaks after every line of code!

Just why.

@wordsandbuttons what's TFS?

@jjsanderson sed would fix it for me. It just boggles me that anyone would write code that way

@pimbellinga What do you do if a student can't explain their work? Write off the whole test?

@honeypisquared Very erudite.

Verudite.

@pimbellinga If you're only checking a sample of students, and one or some of them fail your check, you have to assume some unchecked students also cheated, so punish the whole class. I can't imagine students will think that's fair

Youngest L-P has pointed out that the Indonesian part of New Guinea looks like a dinosaur.

Everything about building mobile apps makes me cross.

@aperfect I'm doing everything. We might need to make an app to deliver to all our students

@aperfect "just build a web app" is the part I can't do. I just need to load a particular URL in a web view

Nice to have this tested in the real world: a student doing a @NclNumbas test lost internet connection halfway through the test. Fortunately, all data is duplicated in local storage, so later that evening they re-entered the test and all the data was saved back to the DB. Phew!

@AdrianJannetta @NclNumbas No, it was a CBA that they had all week to complete

@jamesgrime @stecks I was about to say #spoilers, but if the spoiler raises more questions than it answers, is it a spoiler?

The toddler has started using the words 'maybe' and 'probably'. Time to inoculate her against frequentist interpretation.

Real-world analysis: for any ε>0, there is a dog δ such that δ's whiskers are within ε of my toast.

Rats, that's another space on the lock down bingo card crossed off. 🍞

Finally got a quiet moment to record a #BigMathOff pitch.
Big fan of whatever this is that my face has decided to do

@letsgetmathing My bro was delivered 3kg of bread flour as a substitution for something else he wanted, so he gave it to me. I'd be in trouble otherwise!

Now up to 7 #BigMathOff pitches. Nearly time to start!

An interesting example of Brouwer's fixed point theorem: I think the tummy button of the snowman on the girl's PJs lines up with her own tummy button.

I now realise that I've added another exponential growth problem to my life.
Fortunately, I've already got a mathematical model for this one aperiodical.com/2012/05/grow-y…

My wife is a primary teacher and while her school don't use quite as many services as this, it's still too many passwords to remember.
I wonder why LTI hasn't taken off in primary like it has in higher ed. twitter.com/dibsonmuad/sta…

Just fitted a new aerator to the tap on the bathroom sink. Now in full control of flow rate. Feel like Handy Andy crossed with a Pharaoh*.

[*] en.wikipedia.org/wiki/Hydraulic…

@honeypisquared stretcher for a subbuteo player

Print your own dobble!!
print-and-play.asmodee.fun

@AnonMathMom At least you got to watch different episodes. We've been watching the same episode of Bing since February

@RrrichardZach @Brightspace @CanvasLms QTI is the standard format for representing quiz questions. Apparently D2L's export is in QTI format: community.brightspace.com/s/question/0D5…

@tim_hunt @RrrichardZach @Brightspace @CanvasLms well yes, but for copying MCQs between systems it does the job, doesn't it?

@tim_hunt @RrrichardZach @Brightspace @CanvasLms though having spotted your post on the moodle forum, I see now that D2L adds a load of unhelpful rubbish. Oh well!

I've just discovered that if you paste markdown into WordPress it converts it to HTML for you. That's nice!

this is like the time I discovered that Jabubul automatically refronds TRV receipts from PlasNost

@tim_hunt @RrrichardZach @Brightspace @CanvasLms yeah, I assumed D2L would at have a common cartridge export, but it seems not

Uh oh twitter.com/mscroggs/statu…

@evelynjlamb Have you been doing the rainbows thing?

@mscroggs @matheknitician @aperiodical that makes me feel *slightly* better

Everything in the L-P household is decided democratically. Starting to think the toddler is gaming the system. I don't recognise these voters but she's on first name terms with all of them.

youtu.be/qYlWjxs3BSQ

Back on my animations nonsense.
The toddler came to look:

"You doing maths, daddy?"
"I like that maths!
"How is that maths?"

Welcome to my webinar on interpreting graphs of exponential functions, "Beware the Log"

Just worked out the punchline!

@click_arun node.js with the 'canvas' package to render frames, then ffmpeg to turn them into a video. Source code at github.com/christianp/ani…

@natluurtsema morphology? en.wikipedia.org/wiki/Morpholog…

Have just realised that @jamestanton's exploding dots is the same thing as Papy's minicomputer.
Now excitedly awaiting his treatment of Papy's "Groups" youtube.com/watch?v=RnLOmc…

@jamestanton Have you seen this? rkennes.be/Papy-Minicompu…

It maps pretty well on to a lot of the 2→1 exploding dots stuff.

@PaulsPrattle @jamestanton The same

@GhostMutt did anybody *not*?

@matthen2 did you see Stephen Wittens' version, back in the day? acko.net/blog/how-to-fo…
Yours is easier to follow, I think

Five minutes back and forth with @overleaf claiming it's never heard of \mathbb until I realised I hadn't done \usepackage{amsmath}

@overleaf could the help message "if it's part of a package, make sure you've included it" recommend the package to use for widely-used macros like this?

The Baby Buddy app from @BestBeginnings is really good. Each week it gives a rough size for the foetus along with a similarly-sized object to help you visualise it.

(and also a creepy drawing of the foetus which you shouldn't look at while eating)

(1/2)

Unfortunately, 'size' seems to mean 'length', with no consideration of volume or eccentricity.

So, in the last few weeks, L-P mk2 has been:

A tea bag 😊
A bar of soap 😐
A tin of beans 🥴
A CD 😬
A pen 😅

I don't think anyone would say those are in increasing size order.

Quiz: the doctor has found a stray object in your fundament.
Pick the one you really don't want it to be:

@Helenintgarden @aperiodical @james_a_9283 @K_Severn The poll plugin seems to be erratic about who it allows to vote. The buttons are there for me, and for the 14 people who have voted so far

@ben_nuttall that might just be you. For me it says 12:xx

@ben_nuttall it's 12:xx on WhatsApp web for me too. I wonder if it's a localisation thing

Couldn't do anything else, so made a wobbly clock

@glitch what does ""Project <project-name> suspended: Suspending for too many remixes - contact support" mean? I wanted to choose a project name, and it turns out someone else already has it, but viewing their project gives that message

I've made it into a full, real-time clock: wobble-clock.glitch.me

yesssss

@kyledevans @yppahpeek 12:00 is going to be good

@kyledevans @yppahpeek phwoarrrrr

The good thing about the way that Linux works is that asking JS to allocate a list with 5^100 elements in Firefox has crashed my entire system.

@KangarooPhysics nice!

@dj__error Javascript

@ben_nuttall @pickover That's-a me!

@DanDin01665436 @dj__error github.com/christianp/ani…

This reminds me of every meeting I've ever been in where we propose changing to a drastically improved process twitter.com/howie_hua/stat…

@mikeydoubled @round Thanks for making me feel bad!

@sharpestthought I reckon you could cheat with electromagnets to hold the end in place

I tried the #BigMathOff and I'm up against the editor of Math Horizons! @TedG has pitched a really good bit of number theory that I'm not sure if I've seen before.
I had fun trying to record a video about fusible numbers. twitter.com/TedG/status/12…

The first week of the #BigMathOff lock-down edition is almost done and we've still got enough material for at least a couple more.
Thanks to the players so far, @mathspace, @matheknitician, @kyledevans, @samjshah2, @james_a_9283, @K_Severn and @TedG, and the players yet to come!

And thanks to @james_a_9283, @SamHartburn, @mathforge and @stecks for helping with the admin, because I've just realised I haven't acknowledged them for that yet! The #BigMathOff wouldn't happen without them

@mathforge @james_a_9283 @SamHartburn @stecks I meant you!

*opens BSL dictionary app*
"ooh, videos, better make sure my sound's turned off"

Going to try this today twitter.com/c0mplexnumber/…

@matthras @futurebird @TChihMath Give @NclNumbas a go - it can create printed worksheets as well as the usual interactive quizzes. If you really want it to be a markup language instead of using the graphical editor, you could always write the question files by hand

@Kit_Yates_Maths The pessimist's view could be that this rule won't work as a deterrent for people who don't understand exponential growth

@drvinceknight I just... use git?

If anyone felt like making an anonymous #BigMathOff pitch, that would help me out...

@k_houston_math @C_J_Smith Once online exam hell is over, I want to have a look at making coursebuilder easier to use

@statto As they say, you're always preventing the last pandemic

Solipsists: what if nothing exists?

Mathematicians: what if nothing DOESN'T exist? twitter.com/wtgowers/statu…

@peterrowlett the two-year-old version of this is that things in the gardens have numbers, and we take turns shouting "run to 3!", "run to 1!" and so on. Recently she introduced number 7, which turned out to be "behind the little tikes car"

@peterrowlett I think so. I haven't pushed her to derive an incompleteness/inconsistency result

The expression " 2^x / x^2 " is a palindrome when written in that syntax, but has a sort of rotational symmetry when laid out as a vertical fraction.

@mikeandallie @MrHonner I haven't seen a counterexample to that, yet

@SciencePundit @evelynjlamb Or, I flippantly considered drawing the 2 with an 8-segment display.

@SciencePundit @evelynjlamb Wait, I mean 7-segment

Just used @overleaf 's "compare versions" tool to see what changes my collaborator made, or rather didn't make, last night.
A++ would recommend (Overleaf, not the collaborator)

@sangwinc @ColinTheMathmo Loogabarrooga!

Just accidentally discovered that Ctrl+Shift+X switches the direction of text in a text area in Firefox. That was a very confusing 30 seconds!

I was jealous of how much fun the toddler was having with her Memory game, so I made my own. It's absolutely huge. absolutely-huge-memory.glitch.me

@Thalesdisciple @hannahnpbowman Mine's the same age as yours. Yesterday she made potions using water with food colouring in it and blossom petals, then she painted the nails on some hands drawn on cardboard. Today we're going to bake some cakes and then try connect the dots with chalk

@mscroggs

@mscroggs

I couldn't possibly comment on any large donations I might recently have made

springerlink.com is giving a rather cool 404 message for every page at the moment. I'll take this as a sign that I shouldn't be doing maths

The @CBeebiesHQ programme DipDap just showed a monster dividing a cake into five pieces with two cuts. Is this what I pay my TV licence for?!

Mrs L-P immediately pointed out that if the cuts aren't straight lines there's no problem. I retract my complaint.

I thought more people would be interested in my absolutely huge memory game (absolutely-huge-memory.glitch.me).
It wasn't straightforward to implement; here's a little explanation of how it works

tfw you make something that appeals to exactly your brand of autism

@ZenoRogue I made a hyperbolic version a while ago. It's impossible.

@ZenoRogue Yeah, but 'small' has to be a very small number. If the view auto pans to whichever tile you pick, it could be as small as three tiles and it'd be very easy to get disoriented

@josstified Autodesk Sketchbook's time-lapse feature

The #BigMathOff submission queue is running low, but I've just prepared two pitches. If I pit myself against myself, I'm guaranteed to win.

Am I that much of a chicken?

@icecolbeveridge so you're saying you're up for a best-of-three Beveridge v L-P grudge match?

@anildash @glitch Writing the numbers in "base emoji" is on my to-do list!

@alephJamesA Not sure what non-academic means, but if it's maths I'll take it

This is a good thread twitter.com/blatherwick_sa…

Would you just look at that crumb though!
#SourdoughGoals #SourGoals

@benjamin_leis Cor!

Today's JavaScript headache: Math.pow(Math.E,0.9) is more precise, but less accurate than, Math.exp(0.9).

@lisyarus More precise: more digits given.
Less accurate: those digits are incorrect

@lisyarus that's precisely what I'm doing.

@lisyarus I don't know why you're being so pedantic. I said 'more digits given'. Who are you? Do you just scan twitter for people tweeting about javascript?

@Cshearer41 @ajk_44 @anniek_p @becky_k_warren Thank you all for sharing this! I hadn't fully articulated it before, but now I think maybe "know when to go away and calm down" should be one of the steps in any problem-solving guide.

@Robotbeat @aperiodical She was the first woman, and the first Iranian, to win the Fields medal, one of the top prizes in maths. Her work was mainly in geometry.

@mathzorro intrigued to know how much brute-forcing you did to find those

@PeterKagey Thanks!

Yesterday I could count on one hand the people who thought my waffle about weird maths made them go 'aha!'. Now I need to use my feet too. Vote for @pogonomaths' much more interesting pitch in the #BigMathOff twitter.com/aperiodical/st…

@eqdynamics @EFF Dad it's Wednesday

hey @wordpressdotcom, your "this address doesn't exist" page returns HTTP code 200. Could it return something like 404 instead? For example: wordpress.com/typo/?subdomai…

tfw a pure mathematician tries to write a motivational message

Just over an hour left to vote for @pogonomaths and finger counting aperiodical.com/2020/05/the-bi…

As a person whose job is to make e-assessment software, I'm greatly enjoying the /r/PearsonDesign subreddit as a catalogue of things to avoid. I live in fear of @NclNumbas showing up.
Point: auto-marking maths is hard.
But: please at least make an effort!
reddit.com/r/PearsonDesign

@profRoys Everybody catching coronavirus while celebrating the war would be Peak 2020 Britain.

You, a coward: Python doesn't have a switch statement

Me, a modern-day Galileo:

of course, this has been done before: code.activestate.com/recipes/410695…

Tired: this is baby X Æ A-12

Wired: I have chosen a truly marvellous name for the baby, which this margin is too narrow to contain

Spent too long making this

Today's #BigMathOff pitch by @icecolbeveridge is unexpectedly relevant: are the possibilities *really* endless, bargain bin toy box? twitter.com/aperiodical/st…

@SamHartburn @icecolbeveridge 'The possibilities are finite, modulo your child's imagination!"

Google Maps has sent me my "April timeline update".
#BigData

@Krzysztof_Syruc Fewer

@peterrowlett @mscroggs @matheknitician Outrageous

@mscroggs @peterrowlett @matheknitician Do it quickly, I've only got another couple of days' worth of pitches

@mscroggs @peterrowlett @matheknitician I want it on my desk by 2!

@robeastaway I think this is the motivation: if you give a precise number, you're still thinking of each death individually. If you round off, each death is just part of a statistic. Rounding implies somebody being forgotten, and those in charge caring less.

@robeastaway Absolutely

I see the Nonsense Formula Disapprove-o-Matic 3000 is beeping wildly from the cupboard I left it in, but I have a personal policy of not giving air time to fascists

@peterrowlett looks like you're walking this one!

Drivin' round town
Painting things brown
It's Hugh Laurie
In his hue lorry

You: movies such as "if..." exaggerate the violence of the British upper class as a metaphor for the class system

This public school's website: what's a metaphor?

legitimately thinking of putting this on a babygro for the new arrival

@SamHartburn @peterrowlett @theclairodactyl My plan is to occasionally log in to accept swap requests

Thinking about how every organisation had a "2020 vision" document, none of which envisioned a pandemic precipitating an almost total shutdown of society

@mathforge Python's itertools.permutations has a lovely algorithm for generating tours of every permutation like this. If you haven't seen it, there's an explanation on stackoverflow: stackoverflow.com/questions/2565…

@mathforge @Cshearer41 @RobJLow bah, I'd been saving that up to do next time I get some free time!
Why did you think it might not be possible?

@benorlin Straight to the top of the class, Orlin

@benorlin On a related note, a scene from my market stall:

Me: "quality shapes for sale!"
Them: "enneagon?"
Me: "no, I've still got plenty of stock!"

Uh oh incident-counter.glitch.me/nerdsniping

The #BigMathOff has been running for a whole month! Thanks to everyone who's submitted so far.
There aren't many pitches left in the queue, so it might end this weekend, unless somebody sends more in.
Could *you* be somebody?

Serendipity! I'll be talking about this and other interactive maths things I've made in today's @TMiPUK event, at 3pm BST: talkingmathsinpublic.uk/#tmil twitter.com/SWCHS_Maths/st…

Mrs L-P is trying to upload a video to @Seesaw for her class. The browser keeps crashing on the caption page, when you first see the video. Surely it's not trying to transcode the video in the browser?!

@Seesaw Tried both chrome and Firefox, and another laptop. No other seesaw tabs open

@SamHartburn @nicole_cozens @robeastaway @mrsdenyer That is incredible. Had you been to Slough before then? Did you spend all four days in the hotel or did you venture out to the trading estate? A romantic tour of the pedigree chum factory?

To C, who sent me a postcard about the #BigMathOff: what a lovely thing to do! Thank you!

@peterrowlett Thanks, @sioroberts!

@peterrowlett @mscroggs @FennekLyra @matheknitician @MarHarStar @soupie66 @DrSmokyFurby @MsGreenMaths @SamHartburn @karenshancock @theclairodactyl @Dragon_Dodo @Helenintgarden @notonlyahatrack @LizWindxor I have no idea what's going on. This is starting to feel similar to how Mork and Mindy was a spin off of Happy Days

@SophieBays I didn't know about world baking day, but I'm going to try to turn this into pizzas

@jjaron I set up a personal Funkwhale instance a couple of weeks ago. It's a very good Google music replacement, but needs turbo nerd powers to set up

@icecolbeveridge You nerdsniped me into looking at min/max bounds for the uncertainties in all the measurements. Even my lower bound is still over 60, so you're probably right

TALMO: Baltic trading port or surprisingly-memorable workshop acronym?

Answer: talmo.uk

someone should do a "Baltic city, IKEA furniture, or academic meeting?" quiz

@eqdynamics Of course

@JimPropp You mean two tilings with the same symmetry group? Do you have to preserve the symmetry during the morph?

@matheknitician I wouldn't say "desparate"...

@matheknitician if there was massive demand, but I'm happy with 21 matches

@peterrowlett He might enjoy thinking about muddy children: phiwumbda.org/~jesse/slides/…

@ZenoRogue Are you aware of unicodeit.net?

@ZenoRogue ah, sorry! I scanned the readme. As you were..

@KarenCampe Last time I looked there were another two pitches, so you've got a couple more days at least

This is how pros do US to metric conversions: measure a liquid by weight, add a digit of precision, and shift the decimal point to end up incorrect by a factor of 10.
Glad I stopped to think if that measurement sounded reasonable!

@RealityMinus3 Oh yes, they made that error too!

@heavymetalmaths @Mathgarden Infinitely many! news.liverpool.ac.uk/2016/01/12/mat…

Catching up on my reading, here's a post from Turismo Matemático relevant to @pogonomaths's #BigMathOff pitch (aperiodical.com/2020/05/the-bi…) : a panel from Frankfurt am Main showing counting on fingers mateturismo.wordpress.com/2020/04/27/la-…

Dyspraxia is thinking about whether you also need to shave while picking up the shampoo bottle, then finding yourself staring at the shampoo trying to remember if it goes on your hair or your chin.

When I want to know what 3 quarts is, I just look at the bottom of my pan.
(#CheckMyPanPrivilege)

@evelynjlamb "The first number with N distinct prime factors" grows like the factorial of N. That makes 30 seem more reasonable to me.

@heavymetalmaths @KarenCampe @peterrowlett yeah, on Sunday we had nothing, and now we have another week's worth of pitches!

@AlexKontorovich @evelynjlamb I knew someone would pick me up on this! Point is they're both the product of an increasing sequence, so grow quickly

@icecolbeveridge Yes, I realised this morning that we're back to the 'perpetually imploding government ' phase of tory rule

@samjshah @KarenCampe @aperiodical Voting ends on Thursday

Dyspraxia is your wife finishing making your sandwich for you because you spread a dollop of mayo *next to* the bread.

Twice.

@FryRsquared @kyledevans @geoffreydahl Do you know @lyd_w? These comics are exactly her sort of thing

@carolspringett5 @soupie66 sorry, I haven't really been playing the sticker book game

@gregeganSF @JDHamkins Trivial for you, but someone who isn't well-practised in proof methods wouldn't come up with that quickly

@k_houston_math How many hundreds is it now? Should I be worried?

@k_houston_math 😬

The #BigMathOff is close to ending again, unless some more maths appears.
If we get to 26 matches, that's 52 bits of maths, aka a full deck of cards. Exciting spin-off opportunity?
#spinoffportunity

@peterrowlett I wouldn't mind if it did end

@mathforge that's not a stat I'm interested in calculating

Someone has just emailed me a powerpoint containing a single slide, which contains a single link, to the thing they want to show me.

Do they not know that you can put links in emails? I get people putting screenshots in powerpoints, but this is a step beyond

Now imagining the cursed corporate email system that forbids links in emails "for security", but allows powerpoint attachments so anyone can get their work done.

@panlepan @ColinTheMathmo I also do this, and am also quickly shouted down

Simon Plouffe has found a sequence of 565 primes in 'geometric progression' (meaning they're the closest integers to the first 565 terms of a geometric sequence)
Wowza!
Some explanation at plouffe.fr/NEW/Formula%20…

@Shona_Mu Yes! I've sometimes felt like I need someone, even just one person, on the other side of the screen to direct my talk to.

I'm at the "linter reports 3000 problems with the documentation" of preparing a code release

@ben_nuttall I thought I hadn't made a YouTube account until quite late on, but it seems I beat you!

If you feel like you need to make a visual statement of (1) your beliefs and (2) your mega-nerdity, @realKatePoirier's brilliant "Math for equality" badges and shirts are just the thing: zazzle.co.uk/store/mathfore…
They're expensive but that's because the proceeds go to @BEAMmathHQ

@AudiC @MinoritySTEM @ch_nira @aperiodical I've encountered more than enough professional mathematicians who claimed not to know of any notable Black mathematicians

I have started writing the release notes for @NclNumbas v5.0!

Where do UK people buy computer bits from when avoiding amazon? Specifically, I want a USB webcam. Options less heinous than Argos and Curry's, please. Back in the day it was dabs, but that seems not to exist any more

@TimandraHarknes Thanks! But it looks like they've sold out of webcams

@matheknitician Yeah, I did but the framerate was quite low. I have a webcam on my laptop but I want something higher quality

I'm going to try making plaited bread. This will involve some group theory.
Follow along with me!
First, here's some dough that I've left to rise and just knocked back

I've divided it into 8 by cutting in half three times

Now I've rolled the bits into strands of equal length.
OK, similar length.

Next I have to connect them up like this, which reminds me of that puzzle about the hydra that I can never solve.

Your man Paul says: "Step 1: place 8 under 7 and over 1 Step 2: place 8 over 5 Step 3: place 2 under 3 and over 8 Step 4: place 1 over 4 Step 5: place 7 under 6 and over 1"
I need to label these tentacles

That looks like this. I think. I might not have done exactly the right thing, but I've definitely done some overs and unders.
To answer a comment: the numbers refer to positions, not tentacles, so you relabel after each step

So the immediate question is: where did each strand end up?
The steps are, in permutation notation (I say where each strand ends up) :
(2,3,4,5,6,7,8,1)
(1,2,3,4,6,7,8,5)
(1,8,2,3,4,5,6,7)
(2,3,4,1,5,6,7,8)
(2,3,4,5,6,7,1,8)

You can work out the final permutation by applying those in turn, to get:

(8,4,5,6,7,1,2,3)

So things don't end up where they started.

So... how many times do I have to do this to get them back where they started?

(brief intermission while some parenting happens)

One dance recital, one full potty and a cuddle later, I'm back!

This cycle includes every strand, so I don't get to do a fun bit of maths. I was hoping it'd be several disjoint cycles - cycles that don't share any strands.

This cycle is 8 elements long, so if I apply it 8 times I get back where I started.

You can write that permutation, (8,4, 5,6,7,1,2,3) as a cycle: now (a, b, c) means "a goes to b goes to c goes to a"

That is:
(1,8,3,5,7,2,4,6)

If the permutation *had been* a product of disjoint cycles, I could use a cool fact to work out how many times I need to apply it: the least common multiple of the lengths of all the cycles.

That's what I get for trying to apply maths in the real world...

Fans, I forgot to keep count. Let's say I did it a multiple of 8 times so everything's back where it started.

(ignore the big mush of I-got-bored at the end of this plait)

The Proof and the Pudding by Jim Henle
press.princeton.edu/books/hardcove…

We'll see if the bread is as good as the maths!

Some books about maths and baking:

That's it! I'll try to add a photo when it's baked.

And How to Bake Pi by Eugenia Cheng
profilebooks.com/how-to-bake-pi…

lol 🌈

@eqdynamics If I was applying my master's thesis, I'd show that it was impossible to undo the permutation.

Oh, wait.

#ff for everyone who took part in the #BigMathOff this year:

(tweet 1 of 2)
@alephJamesA @mathforge @matheknitician @BiggestTriangle @K_Severn @pogonomaths @samjshah2 @ZoeLGriffiths @kyledevans @El_Timbre @SamHartburn @TedG @honeypisquared @ZenoRogue @peterrowlett

@alephJamesA @mathforge @matheknitician @BiggestTriangle @K_Severn @pogonomaths @samjshah2 @ZoeLGriffiths @kyledevans @El_Timbre @SamHartburn @TedG @honeypisquared @ZenoRogue @peterrowlett #ff for everyone who took part in the #BigMathOff this year:

(tweet 2 of 2)
@heavymetalmaths @mscroggs @icecolbeveridge @intersectarian @PeterKagey @wsbarhem @alexcorner @VickyMaths1729 @markdcloud1 @FergusPowell @MarHarStar @jamestanton @Clare_L_Wallace @KarenCampe @TeaKayB

@alephJamesA @mathforge @matheknitician @BiggestTriangle @K_Severn @pogonomaths @samjshah2 @ZoeLGriffiths @kyledevans @El_Timbre @SamHartburn @TedG @honeypisquared @ZenoRogue @peterrowlett @heavymetalmaths @mscroggs @icecolbeveridge @intersectarian @PeterKagey @wsbarhem @alexcorner @VickyMaths1729 @markdcloud1 @FergusPowell @MarHarStar @jamestanton @Clare_L_Wallace @KarenCampe @TeaKayB and again for my indispensable helpers, who did so much admin to keep things ticking all along: @alephJamesA @SamHartburn @mathforge and @stecks

This is a highly intriguing integer sequence entered into the OEIS by Scott Shannon oeis.org/A328680
I didn't rediscover it: I chopped the first 1,000 terms off a completely different sequence, and that was the only hit. I have no reason to believe there's a link. How odd!

@peterrowlett @icecolbeveridge @WrongButUseful brb, getting "Bigger than the Beatles (under certain choices of metric)" printed on a t-shirt

Tweet 1 of this thread mentions a person I've had enough of, but the rest of it is a brilliant argument for trans inclusion twitter.com/NMRLPH/status/…

Petition: Introduce Mandatory Ethnicity Pay Gap Reporting petition.parliament.uk/petitions/3001…

Once I spent most of a metro journey agonising over what to do, weighing up my own beliefs against others' rights, then just before we got to haymarket I very discreetly peeled a national front sticker off the window next to me.
Wish I was as brave as the statue topplers

While gathering links for today's school EDI meeting, I came across this ace article by @drchris_maths on Gurruṯu, which I always mention as a great example of a dynamical system but can never remember the details of: teachermagazine.com.au/articles/indig…

The batch number on my shampoo bottle is 9⁴.
#ShowerThoughts

And to think some people have the impudence to ask what's the point of divisibility tricks!

@d_yellowlees How often do you do this?

@NowOverAndOut glitch.com gives you a terminal.

@d_yellowlees yeah, I'm interested but don't have the spare time this Thursday

@DavidKButlerUoA @close It's not in the OEIS! 🤯

@benjamindickman @DavidKButlerUoA @close Ah, I had 19 in it, which was wrong

I've taken the day off normal work to support the #Strike4BlackLives #ShutDownSTEM, but I've got the 2yo all day, so I need something to do in my head. I'll try planning my 'inclusive e-assessment' talk for @EAMSConf

I want to try this with other triangle centres, particularly ones that can go outside the triangle t.co/LitEuD6EgX

Pogs! Memories!
Who else got a set of Sunderland City Council pogs from school with messages about refuse collection and libraries? t.co/OPuGoXwWfd

This is one of the first paintings I can remember noticing and appreciating. Such a calming scene. twitter.com/LaingArtGaller…

When we started planning to run @EAMSConf online this year, one of my main reasons was how hard it is for many to travel to the UK.
We've had more international registrations than normal, but still largely UK, EU and USA.
I want to do more to reach outside this bubble.

So, please spread the word: @EAMSConf is a free, entirely online conference about e-assessment in mathematical subjects, largely focusing on open source software. It starts 22nd June. More info at eams.ncl.ac.uk

@chalkdustmag @SparksMaths sorry, the version of me that has abundant spare time isn't on twitter

I keep seeing photos of 'packed' beaches and parks in the news. I'd like to see how that compares to the density of people in a terraced street. If the walls weren't there, what would it look like?

Problem: people signing up for a conference sometimes make typos in their email address.

Solution: bulk email the entire participant list, and wait for "message undelivered" responses.

@permutans here's my code: gist.github.com/christianp/a92…
Looks like a pretty brute force program!

Currently stuck in a very British conversation that could be replaced by the following program:

10 ECHO "Great, thanks."
20 GOTO 10

@El_Timbre Great, thanks.

@aperiodical A #piku about the sum of the reciprocals of the square numbers:

π × π
is
six times greater

@k_houston_math I'm going to hang on until we're back with the quadrivium

Very much enjoying using @explainevrythng to record my @EAMSConf talk.
First run through, with lots of pauses and umms, took 10:51 of my allotted 10:00. Not bad!

My turbo professional @EAMSConf hosting setup.

Mathematicians working in French universities: do you do any kind of computer-based assessment? What systems do you use?

Mathématicien(ne)s travaillant en universités françaises: est-ce que vous faites des évaluations sur ordinateur? Quels systèmes utilisez-vous?

The difference between necessary and sufficient conditions: they say only mad dogs and Englishmen go out in the midday sun, but while this Englishman is happy to go out, my mad dog is not.

Je voulais peut-être dire 'devoirs', je ne sais pas le mot juste

@mathforge @bbarber_ @peterrowlett "The Haskell road to logic, math and programming" (staff.fnwi.uva.nl/d.j.n.vaneijck…) is very good. There seems to be a PDF on Kees Doets' homepage

Me: storytelling is a wonderfully creative activity. Starting from a basic plot I can refine the story each time I tell it.

The toddler: if you so much as change one word from last time I swear I won't sleep until 2050

How high does zoom's market cap have to get before they let you use a 24-hour clock in the date picker?

@northumbriana @NewcastleMedSch Me too! How much worse than chance did you do on the rearranging-colours task?

What do you think the difference between "Maybe" and "Not sure" is?

The council cabinet has 10 members. "Balance" would be 5 men and 5 women (assuming a gender binary...)

What are the chances of exactly that happening in a meritocracy? Just under 25%. Far from odds on! (wolframalpha.com/input/?i=10+tr…)

Let's take Greg in good faith and suppose he wants a meritocracy, where gender isn't considered.
So each position has a 50% chance of being filled by a woman. (1/N)
twitter.com/nick_forbes/st…

Of course, there is widespread gender bias, in favour of men, so this cherry-picking is either ignorant or dishonest. It's certainly not evidence that there's a problem of too many women.
You can make just about any stat you like with a small enough sample.

The chance of having 7 or more women is just over 17%. (wolframalpha.com/input/?i=10+tr…)

So even if there was no gender bias, you'd expect 1 in 6 councils in the country to look this imbalanced (or 1 in 3 if you include imbalance the other way, with 7 or more men)

@FergusPowell Zoinks! What does your supervisor do? I'd hope every supervisor would recommend a reference management system these days

@ptwiddle @FergusPowell I bet you've got a hand-me-down TeX template as well, you monster

@Kit_Yates_Maths I'd really like a public spreadsheet listing named theorems or objects, next to alternative names. Might set that up

@roger_mansuy J'aime beaucoup le fer à repasser! Je vais l'utiliser moi-même.

@roger_mansuy Incroyable

@mscroggs @pecnuts never mind hats, did you know there's a latex package for ironing symbols? twitter.com/roger_mansuy/s…

No idea why my phone completed @Pecnut to @pecnuts

@LucasVB But I have ℵ₁ wishes

@sangwinc That's brilliant. It winds me up that my daughter's alphabet jigsaw is cut so that some letters can fit in more than one place.

This is a very good book twitter.com/robotmaths/sta…

I've just delivered my talk on inclusive e-assessment at @EAMSConf. The video, transcription, and references are online at staff.ncl.ac.uk/christian.perf…

@robeastaway A knowledge of the rule for deciding who serves is what I'm lacking

@robeastaway can I wave my hands at having identified that point and say I've solved the problem? Feels a bit like that joke about the mathematician who wakes up to find a fire in his room

@robinhouston @panlepan I've definitely looked askance at 39 in the past

@icecolbeveridge which episode?

They said: Cauchy-Schwartz.

YouTube heard: koshish warts.

@katemath wow. "Deeply problematic" is an understatement!

My "mathematicians for inclusion" and "mathematicians for change" stickers have finally arrived!

They're by @realKatePoirier and you can get your own at zazzle.com/store/mathfore…

@aperfect "story"

About to discover if I can send an email BCCed to over 400 people

Based on the number of out of office replies I'm getting, it looks like the answer is yes

Explain why you'll never have to carry a 9 when doing long multiplication

@FergusPowell @gloombario Yep, that's the unexpectedly awkward wrinkle I wanted to share

@evelynjlamb I worry that if someone in a restaurant kitchen is contagious, they're going to infect a lot more people than just the other staff

@mathsjem @El_Timbre I'm a big fan of those pictures.

Not a single place name on this map sounds real.

That's nowhere near an accurate transcription of this video but now I''ve got the opening lyrics for my new album

@DavidKButlerUoA @MathforLove @JSEllenberg Yeah, I've got no idea where the red text is

Supperman.
#AddALetterImproveASuperhero

I'd like to share some thoughts from @EAMSConf, which ran a couple of weeks ago, to help anyone else running an online conference.

We were lucky that we'd decided to do everything online back in January, so all the hard thinking was done before lockdown started.

We decided to go online because of the subject of the conference (e-assessment) but also in order to include more people around the world who would find it hard or impossible to get to Newcastle for a physical conference.

Having decided to move online, we realised that the normal format of a couple of days packed with activities wasn't necessary or even desirable. Unlike travelling to another city, there's nothing stopping you just abandoning an online conference halfway through.

Travelling for a conference is a huge burden in time, energy and money, even when you don't need a visa. Personally, I'm restricted in what I can attend because Ehlers-Danlos syndrome leaves me shattered after a day of travel and standing talking.

So, we set a hard rule of two one-hour live sessions each day, at 9am and 4pm, spread across eight days instead of the normal two.
I think that worked really well, and the feedback from attendees agrees.

And, as most of us have discovered since, staring at a video call all day is knackering. There's also a timezone problem: there are only short times in the day when the UK working day overlaps with the Americas or the far east.

All questions were taken through the course website using a stackoverflow-like interface, rather than Zoom. This worked brilliantly. It let moderators carefully pick and reword questions, rather than the mess of unmuting people, and conversation could continue afterwards.

In the live sessions, we had a chair who introduced speakers and read out questions at the end, and someone else (always me) who played out pre-recorded videos via screen share. This worked better than expected! I forgot the sound a couple of times, but nothing terrible happened.

A lot of the talks were pre-recorded. I think maybe they should all have been. A couple of the non-recorded talks had technology problems, in spite of our efforts to rehearse beforehand.

We initially planned for more interactive sessions, such as workshops for the popular systems, but they made way for more talks. I think we should have made sure to keep them. There was very little of the sort of casual discussion you get at break times in a physical conference.

(We used the MoodleOverflow plugin: moodle.org/plugins/mod_mo…)

"Main", for conference info, general discussion, and reference. The general questions MoodleOverflow was used a bit, but the standard forum and wiki-style reference not at all.
There was an "introduce yourself" glossary which a few dozen people used, but nothing happened with it.

For non-Zoom activity, we set up a Moodle environment. It worked brilliantly, but some bits were used less than I hoped. We really wanted to give attendees an opportunity to see in action the systems we were talking about.
I set up four areas:

"Talks", with a link to the zoom meeting, recordings of all the sessions and individual talks, the question areas, and associated material such as slides. This worked very well.

"Play area", where everyone was enrolled with teacher privileges. I hoped that people would use this to try out the systems we had access to or show off things arising in discussion, but nobody touched it. We'll have to rethink how this should work next time.

"Software demos", with a course for each system being presented. There was a MoodleOverflow questions section for each system, which was well-used.
The stats show that only a couple dozen attendees clicked on anything in these sections.

I don't know how much people who didn't attend live sessions engaged with the non-live material. None of the recordings had more than 60 views at the end of the conference.
We were advised to expect about a quarter of people who signed up to actually attend live sessions.

We kept registration open throughout the conference. We had just over 300 registrations on the morning it started, and 420 by the end. Attendance in the live sessions was in the 80s early on, down to around 60 by the end.

Feedback from attendees: they really liked the stretched-out format, and the short sessions. Most made use of the recordings. Many missed the ad hoc discussion you get in person.

All the videos went on a YouTube channel (youtube.com/channel/UCMN_1…). Every video was initially unlisted, available only through the conference website. Now they're published and linked from the conference website: eams.ncl.ac.uk/programme/

In conclusion: A++ would do it this way again.

@k_houston_math Massive school run envy.

I think I gave my brain a stitch. twitter.com/Mathgarden/sta…

@d_yellowlees Dramatic late entrance, say nothing, write one word on blackboard, wait for applause

@statto Another benefit is it'll mean we finally have a real-world analogy for those infuriating coin-weighing puzzles

@ajk_44 How many spikes?

I have just learnt about unicode property escapes in regular expressions. Wow! developer.mozilla.org/en-US/docs/Web…

@AmyJCast @c0mplexnumber @amanda_l_austin I didn't know I needed flowery Columbus cubes in my life!

@HappeLab I find video meetings more comfortable but also more tiring.

@C_J_Smith Weirdo

@bundlegerbe @monsoon0 @nhoskee I suggest we call them Lawson numbers

Endlessly proud of Mrs L-P. On consecutive days she has voluntarily spotted a prime number *and* a fencepost error!

@InertialObservr @SLSingh did Simon share it somewhere?

@TimahR_S @standupmaths @InertialObservr @SLSingh The most common wrong answers are, in decreasing order of frequency:
51,57,39,1,63,5,69,49,59,79

@mathsjem @greg_roberts86 @MissStokesMaths did it go away?

@greg_roberts86 @mathsjem @MissStokesMaths At first glance I thought you were saying your score was 143 and I nearly had a heart attack!

@peon47 @lukemckinney The short answer is, lots of statements are simpler to state if 1 isn't prime.
For a longer answer, there's this good history paper: arxiv.org/abs/1209.2007v2

@LauraKTully @SLSingh Crikey, tell your 8 year old he did better than I did, and I made the thing!

@icecolbeveridge @evelynjlamb BRB, writing an expository essay about this expository essay about an expository essay.
(Evelyn's post is probably where I first picked up the Caldwell reference)

@MissStokesMaths @mathsjem @greg_roberts86 It's great fun getting a class of kids to shout 'yes!' and 'NO!!!' while one of them attempts to play the game on the projector

"The swing didn't stop, daddy! I wonder why..."

I'll take that as 90% of a law of motion from the toddler. They say just asking the right question is the hardest part of science, don't they?

@evelynjlamb So cool!
I had a tantrum trying to sew a mask, so my 2 year old will have to remain unmatched

@JWGarratt @SLSingh Well done! Was that with the standard time limit?

Next door are having a new conservatory built.

Me, a genius: today I will subtitle two hours of video.

@RobertTalbert I completely agree that we need to trust students rather than set up more barriers, but I don't agree that the incentive to cheat goes away. If I as a student don't want to do any work, I can still get someone else to do it for me under mastery grading.

@northumbriana I thought this photo might get me closer to understanding a tiny niggle that's bothered me for years, but I don't think it does.
Why do the house numbers on Sandringham Drive start at 8? There's nowhere for numbers 1 to 7 to fit even if they had once existed and been demolished

Oooooooh twitter.com/ehardy21/statu…

wow, the Executable Book Project looks good: executablebooks.org/en/latest/
Even on its own, having Sphinx's features with markdown syntax is so good!

@ChronInvisSTEM Who says it doesn't get to go in your CV?

@ChronInvisSTEM You're a nonstandard person! The kind of person they should hire!

I've seen some combinatorial underestimates on packaging before, but this one looks particularly low.
#TheyDidntDoTheMath

@DrCaroSummers In that case, they could have put it as "the vast majority of these clothes clash with each other!"

@jjaron I watched the whole thing recently. It's a quality film!

@evelynjlamb "Maybe the real roots of the function were the friends we made along the way..."

<gif from the end of Buckaroo Banzai>

@alisonkiddle Too many worms. Steering clear of this.

Oh, it's π approximation day, 22/7. I nearly didn't notice!

An estimation problem: how many tweets do you see each day?
I'm tempted to say "wrong answers only", but I'd actually like to know the right answer. So, do either, and it'll be fun to guess which is which

@dichigedamaar @garima_1909 It's a very high score, but not quite the highest. Well done!

Oh my god, I've just remembered I've been waiting since March for a rheumatology appointment twitter.com/chronicallycal…

@JanvierUK SUPERSLUG!!!

@mscroggs @peterrowlett @HappyApproxDay You've given yourself space to improve.

Once I spent ages looking for my keys, but then I found them in the last place I looked twitter.com/fermatslibrary…

@k_houston_math @fermatslibrary I'll guess 'something to do with catastrophe theory'

Just realised my GCSEs are old enough to do their A Levels

We're about to see a spate of newspaper stories featuring people who think 0 is both even and odd, again. twitter.com/NewcastleCC/st…

@peterrowlett @stecks Ah yes, the fiendish villain known as Batman's Complement

10:24. Gotta love it

I have a friend who calls 10:24 "2 to 10". I think it's a brilliant way of getting people to turn up half an hour early

@JimPropp I think this was an abuse of grammar to make the pun work. It took me a while to work out what he meant.

Skilfully dodged the two odd numbered days in a row problem last week! twitter.com/NewcastleCC/st…

I'm sure this must already be a thing, but I can't come up with the right google words to find it, so I've made my own:
A tool to take a subtitles file and a video and make a page showing the transcript alongside the video itself.
github.com/christianp/tra…

At the moment it just copes with Vimeo, because that's where the two videos I want it for are hosted.
Here's one of them: numbas.org.uk/talks/numbas-t…
I have a load of @EAMSConf talks on YouTube, so I'll support that next

@EAMSConf I'd like to know if this is worth having, and if it is, how it could be improved.
I'm particularly interested in accessibility: is it usable with a screenreader?

@permutans I don't think any of the results there do what I want - display a video along with the transcript

Does it bother anyone else that this says x1 and then 1x?

@ZenoRogue @ProfKinyon The - is a list marker, not a minus sign

Me: Today I will get some good honest work done.

Everyone I've ever had any sort of professional dealing with: <just an unremitting stream of nonsense>

If you emailed me today, I value and cherish every interaction with you.

It's just, in aggregate, it's all a bit much.

@honeypisquared What

@JanvierUK keep watching Robin Hood until they cut you off?

It's 5/8, or Almost The Worst Approximation to Φ day!

@mscroggs on a related subject, I can't remember if it was you that told me about this, but just in case it wasn't: have you seen the Ramanujan machine? Lots of nice continued fractions for constants: ramanujanmachine.com

How many decimal digits would it take to write down the number of hamburgers you've eaten so far?

@robinhouston I can describe an algorithm, but it won't be fast

@robinhouston @RAnachro yep, that's what I had in mind

@ccppurcell God help me if I ever try to hire anyone based on their answer to a question like this

@NewcastleEduca1 @UniofNewcastle @Tegglington @NclNumbas @NCLMathsStats This isn't a work account, but thanks!

"Daughter, are your knickers wet?"

"No, daddy!"

Turned out she didn't have any on.
Vacuous truth: the last refuge of the scoundrel.

Chillies! Grown outside! In the North of England!
#SpicyMiracle

I've had answers of 1, 3 and 4 digits. Can anyone credibly answer 2 or 5? twitter.com/christianp/sta…

Rats, my brilliant plan to use just the right amount of annual leave has been scuppered by a bank holiday.

*yells in unpaid work*

@MrBsMaths @mathsjem @Just_Maths @tessmaths There are tonnes. I make one, aimed at Higher Ed but also usable at secondary: @NclNumbas

@JimPropp I think I have seen this book in a second hand book shop!
But sorry, I can't remember any more details than you already have.

@ColinTheMathmo I think you might be missing some context: meaww.com/brooklyn-new-y…

Apart from anything else, I really like that cover twitter.com/DrEugeniaCheng…

@NathanielProf @DisabledStem @ChronInvisSTEM Converting to HTML is the best thing to do. PDF is really only good for print. There are loads of tools that will do it automatically. Pandoc and PlasTeX are two.

Ableism: assuming everyone can access your lectures.

Abelism: assuming it doesn't matter what order you deliver them.

@bbarber_ Nomacs is alright. Works a lot like irfanview on windows

@NathanielProf @DisabledStem @ChronInvisSTEM You can make a single HTML file, which can be uploaded to Blackboard. I can put together some instructions tomorrow

@NathanielProf @DisabledStem @ChronInvisSTEM With pandoc, you need to explicitly ask for mathjax with the --mathjax command line option

@panlepan @geogebra @christianmercat c pas moi!

@FryRsquared I wonder if "A Level algorithm" will enter common use as a shorthand for a statistical error, like the tank counting and damaged bomber problems from WW2.

A helpful message added by IT to the bottom of an email thread in my inbox: "Warning: this message came outside from the university".

One problem: my university, or theirs?

I have a user interface problem that I hope isn't only solved by adding yet another option for authors to understand.

Student types a mathematical expression. We want to allow implicit multiplication, so `xy` is interpreted as `x*y`.
What to do about `pi`? Is it `p*i` or `π`?

My guess is that most of the time, you'd expect it to be interpreted as π. But it's completely reasonable that you might be doing something with complex numbers, and `p*i` is really what you meant.
I suppose rendering π would at least give you a hint to add the * symbol

@GhostMutt It doesn't replace what they type - there's a plain text input field, and a graphical rendering of the interpreted expression next to it. The interpreted expression is then marked.

@GhostMutt I do, but that's not something I want to do

In the vein of "Falsehoods Programmers Believe About Names", I'd like to read "Falsehoods Politicians Believe About Statistics".

If you haven't seen the thing about names, it's by @patio11 and I highly recommend it: kalzumeus.com/2010/06/17/fal…
And there's a list that makes me think every belief held by programmers is false: github.com/kdeldycke/awes…

I'll start the list of Falsehoods Politicians Believe About Statistics. Please add in your own!

1: The success of a policy objective can be measured.
2: There's only one way of measuring success.
3: If the average has increased, everything has increased.

* A 5% decrease followed by a 5% increase is a net zero change.

For reference, @Desmos does implicit multiplication for most letter pairs, but replaces 'pi' with the symbol π. Pressing backspace just deletes the entire symbol. You have to type 'p*i' to get the product of p and i.

@Desmos @geogebra also does implicit multiplication most of the time, and 'pi' is interpreted as 3.14... but it isn't replaced with the symbol.

I've got a half-written @aperiodical post titled "The Enormous Difficulty of Telling the Truth with Statistics" that was mainly about @My_Metro escalators. The alevelgorithm might prompt me to finish it.

@marcuswu I think you're solving the parsing problem, which isn't as hard. What I'm concerned about is the practicality of students using this - they shouldn't be expected to understand how the parser works. They're often shown juxtaposed letters meaning multiplication, so they do it too

@Tony_Mann And 'sin2x' could be just about anything. This is a rabbit hole I don't want to spelunk in!

Add a frisson of peril to statements of fact with the word 'currently'!

My house is currently two miles inland.
Money can currently be exchanged for goods and services.
The official language of France is currently French.

This tweet was prompted by the realisation that we often say "the current Government" but never "the current Royal family"

There are currently 24 hours in a day

@NclNumbas This is a convenience feature that arose from writing this year's exams - quite often we had questions with several scenarios, each with multiple corresponding bits of data.

@NclNumbas The variable generation consisted of making lists of the values for each scenario, picking a list at random, then assigning each item from the chosen list to a different variable. This change makes it possible to do all of that in one go.

I've been seeing all sorts of doctors about why I'm so wobbly since I was 17. Now 34, and we've narrowed it down to "maybe Ehlers-Danlos, see a rheumatologist". twitter.com/_SamBosworth/s…

My computer's processor uses 64 bit addressing AND chessboards are made of 64 squares, each either black or white, BUT I have yet to see a tool which shows my computer's memory layout using chessboards.
#SortItOut

@apgox Henry Ford has two motorised contraptions named after him: the car and the vacuum cleaner.
😐

I'm alarmed to discover I want to learn more about alarms twitter.com/alicecbennett/…

@extremefriday What are all the smoke detectors for? Do they hold a vote?

In undergrad, I lived in a flat whose smoke detectors seemed to be tuned to "someone thought about making toast"

Today I planned to write a series of introductory @NclNumbas tutorials.

Four hours later, still on the first one: nobody has ever given a correct answer to a maths question, and I don't think anyone ever will.

@NclNumbas 90% of my time has been spent trying to find ways around writing "I'm sorry you have to touch a computer in order to make this happen."

@NclNumbas I think the root of the problem is I'm trying to anticipate every possible objection to anything I recommend. Maybe I should just write out a list of instructions, then deal with pedantic objections at the end of the document

@jamesgrime @icecolbeveridge @njj4 *reclusive millionaire superhero Binary Man takes a long, hard look at his finances*

@MrBishopGeog "Is That A Big Number" by @itabn_andrew is sometimes good for comparing big numbers. It says it's 50 times the biomass of the Earth: isthatabignumber.com/itabn/compare?…

Over on mathstodon.xyz, our Mastodon instance for mathematicians, I've just implemented live LaTeX preview while writing a post.

@aperfect I can't remember ever actually playing that

I've made a clock which runs through every permutation of a deck of cards, swapping one pair every second.
It's not very useful.
permutation-clock.glitch.me

This nonsense brought to you by this nonsense: mathstodon.xyz/@christianp/10…

Euler was born 57 years after Descartes died. twitter.com/MathType/statu…

I reckon they meant to say 'independently' instead of 'simultaneously'.
Now thinking about what other facts would be livened up by substituting one of those words for the other.

@Andrew_Taylor @lunasorcery I'm disappointed that the software section is so wishy-washy. Surely public version control would allow someone to find a program whose source code doesn't have a single line in common with its first release

I'm getting strong DO NOT STEP ON THE DANGER GEOMETRY warnings from my hypothalamus while watching this twitter.com/RFJamesUK/stat…

@stecks A model of mathematics is either complete or condescending. #ChangeOneWordAndRuinATheorem

Frantically tidying things up before I go on annual leave followed by paternity leave!

Why is outlook so insistent that I should write "must" instead of "has to" because it's more concise?

I love it when I rediscover an integer sequence with an enormous OEIS entry: oeis.org/A008292

Six years after the last one, I've done another Aperiodical Round Up.
Now *that's* aperiodic! twitter.com/aperiodical/st…

I've made a version which uses a deck of cards instead of emoji, and starts at the unix epoch instead of whenever you open the page: unix-permutation-clock.glitch.me

@lunasorcery I think knowing this was coming made it even better

@peterrowlett @matheknitician @MathsObjects Sorry, my fault yesterday while I was upgrading wordpress

@peterrowlett I think that's enough to pass the stage 1 pure maths module

@peterrowlett @matheknitician @MathsObjects fixed now, I think

In a few days my wife's 99-year-old grandma will have 27 direct descendants down to great-grandchildren, meaning the Lawson family has an R rate of exactly 3

@jjaron I know at least one has a Bacon number

@DrElleOBrien @FryRsquared Ah now, the Perfect R rate is much lower!

@benjamin_leis Yep!

Tribute to Sol LeWitt

@colourblindorg I'd totally follow a twitter account that each day tweeted a different thing and told colourblind people what colour it is.

@soupie66 @colourblindorg Please stop. This isn't funny

@NTCouncilTeam @GoSmarterNT I wish I'd seen this a few hours earlier before I cleaned my bike!

@robeastaway That's a nice one

@samjshah I don't know what this means, but: a POGs round

@cs_kaplan @henryseg @thedicelab I came here to say this. Pity it has negative connotations because it's a strong pun

@benjamin_leis @mathforge @MrHonner @KarenCampe @UDMichy @geogebra @MathforAmerica Ooh, a Geogebra @elmlang binding might be a fun project

I can't imagine what prompted this integer sequence: "Least multiple of n in which the n-th digit from left is 3."
oeis.org/A113558

Our second L-P is finally out. Early reviews describe him as "sleepy" and "cuddly".

@katemath Preferably with a clip of this scene from Good Will Hunting

twitter.com/christianmerca…

The baby's stomach seems to be able to measure three hours to the second.
Is it too late to apply for the longitude prize?

@MathigonOrg @Mathgarden I've encountered this kind of thing as well with @NclNumbas. I usually reply something like "we don't sell anything, I'm happy to answer any questions you have", but I think I'm less bothered about whether they use my software than you are

@FOTSN @standupmaths numbergossip.com/34 says that 34 is the smallest number with the property that it and its neighbors have the same number of divisors.
It also says something @standupmaths probably already knows: 34 is the magic constant of a 4 by 4 magic square

@mscroggs The Kevin Bacon Cinematic Universe

Can't foresee needing to recite an interesting fact about (15-4√2)/8), but in case I ever do, this entry now exists.
Try to guess what it is before you click on the link. I was nowhere near! twitter.com/Parcly_Taxel/s…

Is this a nephroid?

@bbarber_ I'll take either of those over what my former colleague used to do: \;\;\;\,

@IRainsby Alright Magritte, how've you been?

@HoeflerCo Is that equals sign not in the same plane as the people? It looks like it's sneaking up on them

@HoeflerCo Actually, now I can only see this: 😭

@mathhombre I started writing "math is hard" to be provocative, but decided against. But since nobody suggested anything else, here it is.

@robeastaway This is begging for empirical validation. Can it do better than an order of magnitude guess by eyeball? What's the right precision to use for the final estimate?

@robeastaway Yes, I'd be impressed with a number correct to 0.5 metres.
For very plump trees (or wide and deep houses), do you have a horizon problem, where you can't see the very top of the tree?

Tweet me one word and I will reply with a related bit of mathematics.

(until I get bored or the baby needs attention)

@samholloway A cat chasing a mouse on a graph is a well-studied area of problems, e.g. "catching a mouse on a tree" read.somethingorotherwhatever.com/entry/Catching…

@peterrowlett Lava's conjecture states that "Giuga numbers are the solutions of the differential equation n' = n+1, where n' is the arithmetic derivative of n"
arxiv.org/abs/1103.2298

@jjsanderson The song "badger badger badger" in its original form contains the word "badger" 45 times.
(sorry, I can try harder if this is not sufficiently mathematical)

@olliethinks Each of these sandals has fundamental group ℤ³

@ionicasmeets @stecks One of my favourite animals, but the most mathematical connection I can get is that it's name looks like what I say when asked to do a 180° turn: "OK, a π!"

@alancameron65 @stecks "The Phillip Island penguin parade (a mathematical treatment)" by Serena Dipierro, Luca Lombardini, Pietro Miraglio, Enrico Valdinoci
arxiv.org/abs/1611.08715

@b_penders @ionicasmeets "Mathematics, morally" by @DrEugeniaCheng
eugeniacheng.com/wp-content/upl… (a PDF file)

@theclairodactyl I hoped someone would ask for eggs! See this compendious collection of mathematical models for the shape of an egg, by Jürgen Köller: mathematische-basteleien.de/eggcurves.htm

@Manuel_do_rio @stecks I mean, what do you want? My favourite homeomorphism?
Here's a mug that isn't homeomorphic to a doughnut: mathsgear.co.uk/products/extre…

@SvenHilbrants "A singular mathematical promenade" by Etienne Ghys is an excellent book about singularity theory (and lots of other things) arxiv.org/abs/1612.06373…

@BroekeNina @ionicasmeets That's two words, I think?

@rob_m_curry "The hammer and nail phenomenon in mathematics education" by Kien H. Lim

files.eric.ed.gov/fulltext/ED573…

@ionicasmeets @janbeuving Any advice before I lose an entire afternoon to this?

@Marijevhouw @ionicasmeets "Mathematics applied to dressmaking" by Christopher Zeeman contains a fun anecdote about trying to make mathematical sense of a dress pattern
lms.ac.uk/content/mathem…

@edskeizer @ionicasmeets The Levenshtein distance on strings is often used to find the closest correctly-spelled word to a typo en.m.wikipedia.org/wiki/Levenshte…

@IllestPreacha "Treachery! When fairy chess pieces attack" by Christopher Hanusa and Arvind V. Mahankali
arxiv.org/abs/1901.01917
"We introduce a new 1D discrete dynamical system reminiscent of mathematical billiards that arises in the study of two-move riders, a type of fairy chess piece."

@BasHelpt @ionicasmeets "The mathematics of love" by @FryRsquared: ted.com/talks/hannah_f…

@logicmonkey0 @stecks Jim Fowler, Andrew Groot, Deven Pandya and Bart Snapp solve the "no three in a line" problem on a torus by computing Gröbner bases: arxiv.org/abs/1203.6604v1

@jjsanderson I googled the lyrics and did not include the title

@louisabro @ionicasmeets Veel geluk voor te zoon!

@AlistairFrith @stecks "no fibonacci" is a harder than "no graph theory" for leaves.

Avoiding both: here's what's claimed to be the first mathematical model for how buds grow into leaves youtube.com/watch?v=G4lLGT…

@Meromorphic_ I could go and dig up some biomathematics about how endorphins interact in the body, but instead I'll go with a lovely piece of music that produces endorphins in me: Two Dots by Lusine
youtube.com/watch?v=4iIvRX…

@SparksMaths "Liars and their motivation", a series of puzzles in a blog post by Tanya Khovanova: blog.tanyakhovanova.com/2014/02/liars-…

@miclugo will this video on mathematical present wrapping by @stecks satisfy you? youtube.com/watch?v=NwmHHL…

@AlistairFrith @stecks I'm coming back to this because I've just found the thing I first thought of, and I'm unlikely to get 'leaves' again: House of Leaves of Grass, a combinatoric poem: fugitivetexts.net/houseleavesgra…

@EmmaSManning What's purple and commutes?

@ccppurcell @jjsanderson Unlike in set theory, there is often more than one empty sett.

@FranMaths they say you either love marmite or you hate it. Intuitionist mathematicians reject the law of the excluded middle.
In "Meaning in Classical Mathematics: Is it at Odds with Intuitionism?", Karin Usadi Katz and Mikhail G. Katz consider infinitesimals with respect to intuitionism

@ViviennevdWalle @ionicasmeets "Dynamical models of love" by J.C. Sprott
sprott.physics.wisc.edu/pubs/paper277.…
"This paper examines a sequence of dynamical models involving coupled ordinary differential equations describing the time-variation of the love or hate displayed by individuals in a romantic relationship"

@alephJamesA "Train sets" by Adam Chalcraft and Michael Greene proves that model train sets are Turing complete.
monochrom.at/turingtrainter…
I can do 'trains' again if needed.

@BracewellMr @stecks Paul Erdős offered cash bounties for solving mathematical problems. After his death, they were administered by Ron Graham. I'm not sure if anyone's taken over since Ron died this year.
Here's an article about them: quantamagazine.org/cash-for-math-…

@Pierelint I feel there's something at the back of my mind that would be more appropriate, but I'll pick on "super" and give you "H-supermagic labelings for firecrackers, banana trees and flowers" which is pretty supercalifragilisticexpialidocious
arxiv.org/abs/1607.07911…

@dd4ta "Mathematics with a metamathematical flavour" by @wtgowers
dpmms.cam.ac.uk/~wtg10/metamat…

@sara_marine Sticking to what you know, is it?

"Index of Lie algebras of seaweed type" by Vladimir Dergachev and Alexandre Kirillov
emis.de/journals/JLT/v…

@RamakerNiels "Cool irrational numbers and their rather cool rational approximations" by Francesco Calogero
link.springer.com/article/10.100… (sorry, closed access)

@aa42john "The perils of birth weight--a lesson from directed acyclic graphs" by Allen J Wilcox
pubmed.ncbi.nlm.nih.gov/16931545/

@honeypisquared "Why does women's fertility end in mid-life? Grandmothering and age at last birth" by Peter S. Kim, John S. McQueen and Kristen Hawkes
arxiv.org/abs/1906.12048
(link does not equal endorsement)

@theblub Is that a word? I can barely see it

@theblub "The accuracy of Buffon's needle: a rule of thumb used by ants to estimate area" by S. T. Mugford, E. B. Mallon and N. R. Franks.
academic.oup.com/beheco/article…

@honeypisquared I have a feeling I've seen this paper before in the context of an angry refutation.

@RichardElwes Rhombicuboctadodecahedron

@honeypisquared Looking forward to their follow-up paper, "Men: Why?"

@honeypisquared en.m.wikipedia.org/wiki/Sokushinb…

@benorlin I can't do you a koala, but I can do you a kangaroo: "How long does it take to catch a wild kangaroo?" by Ravi Montenegro and Prasad Tetali
arxiv.org/abs/0812.0789v2

@TobyBailey "Haruspicy and anisotropic generating functions" by Andrew Rechnitzer
sciencedirect.com/science/articl…

@KerryLiles I hope you'll accept something that applies to any citrus: "Orange Peels and Fresnel Integrals" by Laurent Bartholdi and André G. Henriques.
arxiv.org/abs/1202.3033

@dandersod "Battling over barrels" by William Deringer in cabinet magazine is a brilliant essay on the development of calculus and statistics to establish the alcohol content of beer. Subscription required, sorry, but @cabinetmagazine is fabulous.
cabinetmagazine.org/issues/49/deri…

@PickAardvark Ramanujan was famously perspicacious. The most widely know examples of this was when he remarked that the number of Hardy's taxi, 1729, is the smallest integer that can be expressed as a sum of two positive integer cubes in two distinct ways.

@Rosalot I can do you another fish: the mathematical tetrodon. Mathematical only by name, I think. publicdomainreview.org/essay/dr-mitch…
How the devil are you? It's been ages!

@Rosalot Well, here's a mathematical not tion editor called Guppy: guppy.js.org/site/

I'm good, still at Newcastle uni, currently on paternity leave for my second born

@macaronique Robert Recorde, in his Whetstone of Witte, coined the term 'zenzic' to mean the second power of a number. He repeated it to produce higher powers: 'zenzizenzizenzic' means the eighth power.

@george_jessup Get a strip of paper. Fold it in half. Then fold it in half again. Keep folding it in half. When you unfold it, it produces a fractal curve called the Heighway Dragon. It tiles the plane!
larryriddle.agnesscott.org/ifs/heighway/h…

@dd4ta @wtgowers What would that involve? Do you mean an explanation of how you go from "I think this might not be provable" to "this definitely can't be proved?"

@wtgowers @dd4ta That's the page I linked to two tweets up!

@wtgowers @dd4ta I mean, it's a good page, I think it holds up to being linked twice

@Meromorphic_ Yes, it's a very good movie!

@yet_so_far Darn tootin'. It's from the biopic of Shakuntala Devi - highly recommended!

@RogerWolff2 The sieve of eratosthenes is a dreadfully slow means of finding prime numbers

The "I'm feeling lucky" of twitter engagement twitter.com/RogerWolff2/st…

@blatherwick_sam I've been discussing graph sketching with the @isaacphysics people, who are trying to automatically assess sketches. It's hard to pin down what a sketch of a graph is. I agree with what you said.

@BrewEdMaths @woodhouse_a The pattern made by reflected light at the bottom of an empty mug is called a nephroid. It's not a cardioid, as I thought for a long time.

Parenting first child:
CAN'T BLINK, BABY WILL DIE.

Parenting second child:
"Do you know where the baby is?"
...
"The new one."
...
"No, me neither."

@aa42john The NHS will shortly be making that an impossibility

@HilariousCow So that's equivalent to multiplying the rotation by itself, but the benefit of this way is that you can do fractions like 1.5 times more easily?

I've always got time for a clerihew twitter.com/tentivetodetai…

@wtgowers I won't just say you should move to a host that does proper LaTeX, though I can help whenever you want to do that.
Until wordpress.com fixes their bug, here's a bookmarklet which replaces their images with MathJax: fix-wordpress-dot-com-maths.glitch.me

@wtgowers I'm not sure what hosts offer it, but it's a built-in feature of the WordPress software. "WordPress multisite" is the thing to search for. You want that plus the ability to add plugins, for MathJax.

@wtgowers What isn't always clear is that there's wordpress.com, the free service run by the company that makes WordPress the software, which is open source and can be installed and run by anyone. There are plenty of companies offering hosting for WordPress configured as you like

@peterrowlett @MathEdSciTech Now there's a blast from the past!

While the baby is sleeping, I'm having fun working through the Lean natural numbers game wwwf.imperial.ac.uk/~buzzard/xena/…

So far, I'm repeating the background reading of the PhD I never finished. I'm glad I didn't finish, because Lean makes it superfluous

If anyone wants to pay me to write "Proof assistants for babies", I'm open to it

@standupmaths @stecks have you seen this anamorphic football pitch in Nantes? mateturismo.wordpress.com/2020/09/17/fey…

@virtualcourtney @Thalesdisciple @dzackgarza Are you getting images of maths notation to paste in to tools that don't support LaTeX? You might get on with this that I made, to do this quickly: checkmyworking.com/misc/makebigma… Just take a screenshot of the rendered maths when you're done

Paternity leave over. Yikes!

How do you feel about a video transcript using mathematical notation, e.g. "∑ x²" instead of "the sum of x squared"?
My hunch is that the fact notation isn't always read strictly left-to-right would make following both the video and transcript harder.

@northumbriana What was your dad doing to his suits that he needed three a year?!

@stecks @standupmaths ... I now have a feeling that might have been me

@Kit_Yates_Maths @standupmaths Oh my god, I think I know which line of the PHP config caused this.

@Kit_Yates_Maths my guess, knowing nothing about what happened other than the tweet you quoted, is: they set up a server to upload reports to, running a script written in PHP. The default PHP config sets a maximum size for uploaded files, to prevent errors or attacks which fill the server up.

@Kit_Yates_Maths The default maximum filesize is big enough that you rarely bump into it when testing, unless you have particularly good presence of mind or you've been tripped up by it before.

@standupmaths @Kit_Yates_Maths Adding a line to my professional bio:

"Unsurprising" - Matt Parker

@standupmaths @Kit_Yates_Maths

Time to clock off?

@CopsAndClouds I read them all.
I sent 18 replies while I was going, and flagged 25 to look at later. I received another 15 emails while I was doing this.

@virtualcourtney @Thalesdisciple @dzackgarza ah!

@JimPropp I think I agree with your HR people

@kyledevans I think it's 'pathematical'

@helenarney Helen. Friends don't tell friends about the four month sleep regression.
(Solidarity 🤜)

You, a gentleperson of distinction: two spaces after a full stop.

This hero I'm copy-editing: at least three spaces after a full stop.

Working on moving @NCLMathsStats's material from our private @NclNumbas database to numbas.mathcentre.ac.uk.
1729 good quality questions soon to be published! (What's interesting about that number?)

@jjsanderson To be clear, I only use one.

Have any universities explicitly put an upper bound on the number of Covid cases that they're willing to tolerate and continue face-to-face teaching, or have they all decided that if they don't do that they're not liable?
@NewcastleUniUCU

Day 2: I've cleared the backlog of emails to the @NclNumbas users group, too! I might be able to do some actual new work by the end of the week.

@ColinTheMathmo I can have a look tomorrow if you haven't solved it by then

That's an odd number of rolls

@d_yellowlees Do you find Droid cam worthwhile? I couldn't get it to work at a decent framerate

@d_yellowlees ah, cool

@Maths2014sow Every now and then I relive the shame of my PE teacher in year 9 saying "there's 17 of you. Why's that bad, Perfect?" and not being able to answer

@presentations @d_yellowlees what kind of phone do you have?

@d_yellowlees @presentations I meant @presentations, since he seems to have a magic feature we don't!

@d_yellowlees @presentations that's what I suspected. I've heard iOS devices can share to macs nicely

@joshlaison YES

@presentations @d_yellowlees I do think this is an apple only thing support.zoom.us/hc/en-us/artic…

@helenarney I had it lots when I was little. I remember it as "that fun time I stopped breathing and got to stand over the kettle" but I'm sure it was less fun for my mum

@helenarney My mum combined steam with a homeopathic pill from the homeopath next door. I'm a living control group!

I have a scratch on my monitor exactly where people's profile pictures appear in Outlook. It makes everyone look like Blofeld.
Can recommend.

@helenarney trying to work out which way to round negative years is making my head hurt. I feel like if you're 0 on the day you're born, you should be -1 the day before

People keep writing @NclNumbas in caps as NUMBAS.
Fortunately, Numbas is case-insensitive.

@standupmaths @MiniGirlGeek Would you say you have learned from exp(erience)?

@RobertsDavidJ @robeastaway @ben_nuttall A case of statutory instruments moving faster than the editing process

@RobertsDavidJ @robeastaway @ben_nuttall Though the maximum for a table of 6 is worth working out, if you want to give it a go

@HilariousCow Yes Aubrey!

What dullard called it 'remote exam invigilation' and not Proctors Without Borders?

@HilariousCow Give it a go! They're easier than they look. The hard part is leaving them in the oven long enough so try don't collapse, but even if they do they still taste good.
I can take a photo of the recipe in my daughter's "my first cook book"

In the list of consecutive positive base-ten integers: 1, 2, 3, the 1111111111st occurrence of 1 is the first 1 in 1111111111.

Discovered by Hans Havermann - gladhoboexpress.blogspot.com/2020/10/propor…

@mathzorro @aperiodical I'm going to answer for Katie and say no

@AndreasVohns @NclNumbas @H5PTechnology I've added a ?language parameter to the preview and embed URLs, so you can specify the language to use. For example: numbas.mathcentre.ac.uk/question/74755… is guaranteed to use German.

@gazatron13 you're right!

!!!!! setwithfriends.com lets you change the colours !!!
There are tears in my colourblind eyes

@samholloway which app is it?

@samholloway are there three colours in that screenshot?

@becky_k_warren yes I have

@becky_k_warren I mean, I have no idea what they're called. The hex codes are #800080, #0AEF0D and #E66565. If I was serious I'd get some colours from colorbrewer2.org

@howie_hua How do you feel about '-x'?

@robeastaway is that because you only cut by length?

@robeastaway yes, that's what I was thinking

@DavidKButlerUoA do you have a written set of rules or code of conduct for 100!?
We're setting up a similar thing, and I think it would be good to have stuff like "be nice to each other", "don't give spoilers unless asked" on record

@mozzichi @DavidKButlerUoA that's the way I was taught it in the UK, too

@DavidKButlerUoA thanks!

@DavidKButlerUoA do you mind if I pinch that pretty much wholesale?

One of our PhD students has just passed their viva with no corrections.
I'm in the presence of greatness.

I thought of a brilliant, short domain-name for a self-hosted git server, but just before registering it I realised that owners of a .it domain need to be EEA citizens and I'm not sure if that'll include me after January

@madebyburton yes but l-p-g.uk doesn't work as a pun

@mortal_ordinary The viva is the spoken exam after you've submitted your written thesis. The examinees decide whether to award your degree. Most of the time, they award it subject to corrections - fix the errors or weak bits they've spotted, and you're a doctor. This student didn't have any!

@VickyMaths1729 @LPPbooks Crikey, a #BigMathOff reference on the back!

Congratulations on your new book

@icecolbeveridge What feelings does this python code provoke in you?

max(n for n in range(100) if str(factorial(100))[-n:]=='0'*n)

@ColinTheMathmo @icecolbeveridge that was my first draft, but I thought re was a bit of a sledgehammer

@bbarber_ @icecolbeveridge Conjecture: n! does not have more than n zeros on the end.

@ColinTheMathmo @icecolbeveridge ahhh, I had a feeling there was a function to strip suffixes! Well done

@ColinTheMathmo @icecolbeveridge without strings: max(n for n in range(100) if factorial(100)%(10**n)==0)

@icecolbeveridge @ColinTheMathmo is @ColinTheMathmo's point that the question is "how many zeros on the end?" and your code doesn't do that directly, it uses a theorem which avoids writing out the zeros

@icecolbeveridge @ColinTheMathmo I was getting at that from the other direction - computing for 100 in the most brute way I could think of

Stupid idea: record or write a proof of the same theorem every day for a month.
It's already been done in "99 variations on a proof", I suppose

@ccppurcell Ooh, nice!

@howie_hua I don't think "simplifies to 1" is any better than "cancels to 1". "Simplify" has so many meanings

Something that puts a chill down your spine: an email from the university's executive board that begins "The government has been clear"

300g of sugar into Sunday morning, we've decided not to let the girl watch the Bake-Off any more

@jemmaths @MathsTechnology @onechriswhite @VMN_alex @Whitehughes @mathstiger70 @tm_maths Wikipedia says that's why τ was chosen, so no pretending necessary en.m.wikipedia.org/wiki/Angular_u…

@jemmaths @MathsTechnology @onechriswhite @VMN_alex @Whitehughes @mathstiger70 @tm_maths I mean, I literally just learnt it while trying to look up what gradians are, so that makes both of us

Should it bother me that Sainsbury's obvious Penguin knock-off chocolate is called "polar bar"? They live at opposite ends of the planet!
(In case you're interested: chocolate filling fine; biscuit doesn't have quite the right texture)