Not in nature, but Möbius conveyor belts were patented. Here is a 1949 patent to Owen Harris, for an abrasive belt, as described by Clifford Pickover: <hr /> [![ConveyorBelt][1]][1] <br /> <sup> Image from Pickover, p.44. </sup> <hr /> > Pickover, Clifford A. *The Möbius Strip: Dr. August Mobius’s marvelous band in mathematics, games, literature, art, technology, and cosmology*. Thunder’s Mouth Press, New York (2006). [1]: https://i.sstatic.net/eAPov.jpg