Spinor

thingiverse

With heartfelt thanks to G. t'Hooft, and also as described in the timeless Feynman lectures, this is a demonstration of an object that one must rotate through four full rotations, or 4π, to get back to its original state, rather than just one full rotation, or 2π. Such objects are called spinors, and play a crucial role in classifying states in the intricate world of quantum mechanics. Print out the box and the star game piece. Tie four foot-long threads, each between one of the holes at the ends of the box and a hole in the star game piece in such a way that they remain untangled. That's it! To "play" note that, always keeping the box fixed, if you rotate the star piece around any axis twice the ropes appear tangled BUT by simply translating the star piece (without ever rotating it) through the strings in a sequence you can return the strings to their untangled initial state. This is not possible if you rotate the star initially just once along any axis!