The brain-melting concept of the Möbius strip has been used to explain complex, meaningful ideas such as time travel. But this simple, trivial music box, which uses a punch strip in the shape of a Möbius strip, might be my favorite application of the idea.
The music box will play the song once through, then plays it again upside-down, creating an endless, repeating loop of music. It may not solve the secrets of the universe--but hey--it looks so cool. Can you recognize the upside-down-and-backwards tune?