Video from artist Dave Johnson:

There are three movements, controlled from 3 axles, and the gears on the axles have prime numbers of teeth (23, 43, 59). So technically the movements will only repeat every 58,351 turns of the small gear. There’s also a semi-random toggle on the head motion, so it will never really quite repeat. Almost all the parts press fit and/or lock together, so the whole thing can be disassembled to a pile of parts, then reassembled, adjusted, and set going again without tools.

The formal title is “Sisyphus Testing Shoes; Or, Little Man Tries Real Hard.” There’s also a Flickr photoset of its construction. [via Dug North]