Figure 8.31: A size-distance illusion We know that these young women must be approximately the same size, so what explains this illusion? The room they are standing in is distorted. The back wall and both windows are actually trapezoidal in shape, and the wall is slanted so that its lefthand edge is actually twice as tall and twice as far away from the viewer as its right-hand edge (see drawing at right). When we view this scene through a peephole (or the camera’s eye), we automatically assume that the walls and window are normal, that the occupants are the same distance away, and therefore that their size is different. This distorted room is called an Ames room, after Adelbert Ames, who built the first one.