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Droste Dobble

This goes with a Big MathsJam talk from 2015.

Dobble cards are points on a projective plane.

Each line contains all of the cards with a given symbol.

But a projective plane is its own dual: ifyou swap the lines and points, you get the same structure!

So there's no reason you shouldn't replace the symbols on a Dobble card with more Dobble cards.