A basic spirograph set includes plastic rings (stators) with gear teeth on the inside and outside. Gearwheels (rotors), also with teeth and holes for pens, are spun around the rings to create ...

[Tuchman] starts with a quick proof-of-concept using an actual plastic Spirograph toy to make sure it isn’t a totally unworkable idea. Unsurprisingly, the plastic is too flexible to give a ...