I made a counter to track life points in Magic: the Gathering from 20 down to 0. The design uses planetary gears, which are pretty neat because they rotate without needing an axle.
It’s very fun to watch the little dials spin around. I made a video of it in action
The attached file has the gears and numbers and everything, but I left out the mana symbols because copyright. You can pretty easily find vector versions of those, however, and just stick them in before cutting.
I built everything with Inkscape’s “Render > Gear” extension. I follow this video tutoral for instructions on inverting the outer gear.
The inner gears I also gave a 0.1mm stroke, then used “Stroke to Path” and took the inner paths to make them a little smaller. Kerf by itself was not enough to allow free motion.