“In the same way that a drawing compass allows you to create a circular path around a fixed center point, Spirograph uses moving gears to rotate that path as it is orbiting around the center poin ...

At first glance the monicker “spirograph” seems wrong, because where are the gears? However, [Yoshihito] has them stashed underneath the sheet of paper, with magnets controlling the pens.

[Tuchman] starts with a quick proof-of-concept using an actual plastic Spirograph toy to make sure ... but he needed to adjust gear ratios and ergonomics to make the device more usable.

Spirograph, a geometric drawing device, creates mathematical roulette curves known technically as hypotrochoids and epitrochoids. In simpler terms, it's a toy that uses gears to produce intricate ...