is that the one with dialogue commentary, which got completely deranged as it went on?

"pass through itself" does seem like cheating to me.

This animation and explanation is really good!! The studio, which is guess was new at the time, was called Pixar. According to the credits, one of the animators there shares a last name with one of the mathematicians who developed this method (Thurston).

Not a physical material but a "surface".