A group of actors rehearses a play within a play within a play.
This is optional.
A group of actors rehearses a play within a play within a play. As the plot complications multiply, the actors begin to forget who is playing whom and who is the real director -- as opposed to the actor who is playing the director, or vice versa. Then they can't seem to remember who they really are, as opposed to the people they are playing in any of the various scripts. Then things start to get confusing...