If you ever had a spirograph, or even better if you never
had one: now there's a good one on your web browser!
It's easy to use. You just move one gear around the other using your mouse (or finger). I still prefer the actual spirograph: working with actual physical tools is a much more immersive experience than twiddling a computer. People are getting starved for contact with interesting matter
. But not everyone has access to a spirograph!