Illustrating spin 1/2 with a toy model

Series of short pedagogical movies (one without narration, one narrated in German, one narrated in English) that demonstrate the property of spin 1/2 systems to return to their initial state after a rotation by 720 degrees, but not after a rotation by 360 degrees. The movie shows the well-known analogue system of a shoe suspended by both of its laces being fixed to a bar. After a 720 degree rotation, the initial state can be restored by looping the laces ones around the shoe, without changing the shoe's orientation.