Non-Reciprocal Gears is a set of gears with ratchets. Its mechanism is related to the Non-Transitive Gears. The toy can be presented as a parlor trick. You challenge a friend to choose a gear and turn it. If their gear turns the fastest, they win. If your gear turns faster, then you win. The trick is that if you turn a gear clockwise, what most people do, then it will turn slower than the other gear. So no matter what gear they choose, they lose. But what if they ask you to turn the gear? No problem, you just turn it counter-clockwise (anti-clockwise). That way, again your gear will turn the fastest.
The mechanism took 6½ hours to 3D print on a Dutchy 3D printer. 49 meter of 1.75-mm PLA filament was used to print it. The mechanism weighs 17 grams.
Oskar van Deventer, 5 January 2022
Oskar van Deventer has created many different puzzles including his brand of Oskar Puzzles which are mechanical puzzles and objects that can only exist thanks to 3D printing technology. Since 1978, he has been creating hundreds of mechanical puzzles, making him one of the world's most prolific designers. Several of his innovative designs are commercially available.