Kaleidocycle

A kaleidocycle is a rotating ring of linked tetrahedra that can be turned inside-out continuously without disconnecting. Discovered by mathematician Doris Schattschneider, these structures exploit the geometry of hinged tetrahedra arranged in a cycle. Each tetrahedron shares an edge with its neighbor, and the ring's topology allows a continuous everting motion -- a transformation where the ring passes through itself indefinitely. Click and drag to rotate the cycle, or let it auto-rotate.