_Karl Gerstner, Squaring the circle (1954)
Karl Gerstner’s (1930–2017) graphic work is irresistable—a gift and a challenge—to coders everywhere. Or, at least, to this coder.

It felt to me like wringing winged crosses—or fan shapes, if you like—out of chessboard squares needed to happen in real time for maximal effect. I made this animation of a piece of Gerstner’s aspirational ‘optical torture room’ with Python in DrawBot.

The original graphic, from Designing programmes (1964); this is from Lars Müller’s 2007 third revised and enlarged edition: