The visitor enter a room plunged into darkness. Two holes have been bored on each side of the box. It is penetrated through the first opening by a video-camera. In the second, a video projector (VP) is placed over the aperture. The camera films the hotspot of the VP. The image is then promptly shown by the VP.
The machine is sensitive to its environment. It may panic, crash. It is psychotic. A machine, a camera, a linear rail, a screen, a patient, a psychiatrist, visitors...