This video is about the problem of turning a sphere inside out, by passing the surface through itself, without making any holes or creases. Mathematicians believed the problem to be unsolvable ...

"Normally a sphere can be turned inside out only if it has been torn. In differential topology one assumes that the surface can be pushed through itself, but then the problem is to avoid forming a ...

Outside In builds up to the grand finale: Bill Thurston’s “corrugations” method of turning the sphere inside out.