Something or other, whatever!

Christian Lawson-Perfect's homepage

Regex fractals

Split the space into quadrants. Name them 1,2,3 and 4. Split those quadrants up, and add another digit to the names. Repeat a few times!

Now each cell has a several-digit name. Turn a cell on or off depending on whether its name passes a regular expression. Use the length of the expression's matching groups to colour on cells.

Inspired by SSOΔ.