A Mobius loop (double perf 16mm loop with a twist so it switches left and right with each revolution) in which you can easily see the flip. One of the ongoing "Blueballs Suite" series, starts with ...

The film has two sets of perforations and is twisted into a loop, known as a Mobius Loop. On projection, the strip of projected light switches from side to side, followed by a change in tone of ...

These first 22 films are now called the "Infinity Saga," which makes sense since a Mobius strip resembles the symbol for infinity. Watch all 22 movies all the way through, and you end up back ...