This famous optical illusion is discussed in most psychology texts and courses. The photo at left above shows two identical twins in the same room. This is a single, unmanipulated photo. The same scene can be seen with the naked eye by looking through a peephole in the wall of the room. How would you construct such a room (usually called an Ames Room after its inventor)? Give up? Then click here or here. For a video of an Ames Room and two moving occupants, click here.