I’m sure a lot of you are going to look at this picture and be transported to childhood (either your own, or one of your own children or younger friends): The Spirograph. This deceptively simple collection of geared rings and wheels and pens were the source of hours of drawing fun; You pinned down the big ring, grabbed a little gear full of holes, put your pen in the hole of your choice, and your pen magically drew these amazing curves and shapes inside or outside of the toothed ring as you moved the little wheel on its circular path… that is, unless your hand slipped and the wheel came loose, in which case you started again and learned a little coordination as well as creating cool designs!
https://cycling74.com/articles/rainysnowy-day-max-spirographics