The Cube (1969)

An unnamed man, simply called "The Man" is trapped in a cubical white room where anyone else can enter and leave, but which he himself apparently cannot leave. A stool is brought in covered in strawberry jam, the furniture changes throughout the play. The main character, is subjected to an increasingly puzzling and frustrating series of encounters, as a variety of people come through various hidden doors. But, as many remind him, he can only leave through his own door, so he must find it to leave. Originally airing on NBC's weekly anthology television show NBC Experiment in Television in 1969, the production was produced and directed by puppeteer and filmmaker Jim Henson, and was one of several experiments with the live-action film medium which he conducted in the 1960s, before focusing entirely on The Muppets and other puppet works.