In this format a cast of five gets one ask-for each at the top of the show, and then each person is free to play solo scenes with invisible characters, addressing the audience, musing to themselves, speaking on the telephone, just being physical and so on until another player enters, at which point they have to leave. Over the course of the performance a complete play is done. The actors can play multiple characters if they want.

Origin

Attributed to the Spontaneity Shop (London).