The fourth wall

The fourth wall is an imaginary "wall" which is usually at the front of the stage or set in a traditional three-walled box set. For example, the tv comedy series 'Friends' used this in most of their sets. In monicas flat, the fourth wall was never seen, and the actors never went up to the wall. The idea of the fourth wall was made explicit by philosopher and critic Denis Diderotand spread in 19th century theatre, it extended the idea to the imaginary boundary between any fictional work and its audience. Speaking directly to or otherwise acknowledging the audience through the camera in a film or television program, or through this imaginary wall in a play, is referred to as "breaking the fourth wall" and is considered a technique of metafiction, as it deconstructs the boundaries normally set up by works of fiction. Although people try to avoid breaking the fourth wall, some television programs have broken it to add comical effect.