hexaflexagon: a folded geometric figure made of six tetrahedrons that can be ‘flexed’ to expose many sides.
This video from ViHart is just. so. cool.
Hexaflexagon Safety – a humorous look at the dangers of hexaflexagons.
Because Vi’s video is so fast, its hard to follow her instructions to make a hexaflexagon. Here’s a link for instructions.
And finally, a pattern with designs to color in.