Dirac Belt Trick

dirac belt 2sided 001
Dirac Belt Trick.
The animation shows how one can twist and untwist a belt by rotating the end of the belt always in the same direction. The demo was invented by the physicist Paul Dirac to explain a topological property of the rotation group.
dirac belt anaglyph.png 001
dirac belt anaglyph
Air On The Dirac Strings. This remarkable 1993 animation shows all three classic visualizations of the fact that the fundamental group of SO(3) is cyclic of order two, namely the Dirac Belt Trick, the Phillipine Wine Glass Trick, and Orientation Entanglement. It was designed by George Francis, Louis Kauffman, and Daniel Sandin, and the computer graphics were implemented by Chris Hartman and John Hart.