Magic Gears is a paradoxical set of three identical gears that can both mesh in the regular way and all in the same direction. It was inspired by this YouTube video by Jacques Maurel: https://www.youtube.com/watch?v=7h_Q3GmwShQ. Maurel writes: "The paradoxical 2 teeth gear set is used in the 'Mercier differential' (using the torque transfer technology) Patented in 1988 by Renault". Oskar's addition to the work is making Chevron Gears (http://www.svvs.org/citroen2.shtml20) as invented by Andre Citroen. This way the three gears become identical and they can both mesh classically and paradoxically.

I have performed this Magic Gears "trick" to several friends, family and colleagues. I get two types of reactions: "wow" and "so what". Apparently, there exist people who are not aware how gears are supposed to mesh :-).