Spinor Gears

Spinor Gears are a response to Bram Cohen's challenge when he saw my Fractional Gears, which features one gear with "half-fold" rotational symmetry. The question was whether it would be possible to design a gearing system with two identical half-fold gears, where the system returns to its starting state after 720 degrees of rotation, instead of the usual 360 degrees. The answer to the question is "no", as illustrated by the prototype. Even though the gears can rotate over 620 degrees, by far exceeding the 360-degrees mark, 720 degrees is not possible. The problem is that there will always be a "cross-over point", where there is ambiguity in which "track" the gear set is.

Watch the YouTube video.
Read at the Shapeways Forum.
Read more at the Non-Twisty Puzzles Forum.

Please order a 3D-printed do-it-yourself puzzle kit from Shapeways at this page (check with Oskar about screws and stickers), or contact Oskar directly if you are interested in obtaining a fully colored, stickered and assembled sample of this puzzle.