Someone asked on Facebook whether it’s possible to draw spirograph patterns on a curved surface. This was back in 2023. I was intrigued and thought I’d try.

I had a basketball, which I set in a suitably sized (crystal!) bowl to hold it steady, and proceeded to attach a Wild Gears ring (84 teeth on the inside) with putty and drew a pattern (Wild Gear 36 teeth). And to my surprise, it worked quite nicely.

I wasn’t intending to do it more than once, so I made a video of the whole experiment, which is below.

My basketball will never be the same. I used a black Sakura Micron 05 pen, which is permanent, archival and waterproof. Although I used some Wild Gears, I think Spirograph parts should also work.

Now that I think about it, though, the guy who asked the question was a wood turner. A basketball is spherically symmetrical and convex, so this might work on the convex side of a shallow turned bowl, but drawing on the inside of the bowl probably wouldn’t work as the inside ring teeth would be off the surface. An epitrochoid (drawing on the outside of the ring) might be possible, however, on a concave surface.

I don’t see it working on a spindle shape with cylindrical symmetry.

Here’s the video. Let us know if you try anything like this.