An Ames room is constructed so that from the front the room appears to be an ordinary cubic-shaped room (with a back wall and two side walls parallel to each other). However, this is a trick of perspective and the true shape of the room is trapezoidal: the walls are slanted and the ceiling and floor are at an incline, and the right corner is much closer to the front-positioned observer than the left corner (or vice versa).
The person standing in one corner appears to the observer to be gigantic, while the person standing in the other corner appears to be of minuscule proportions. The illusion is so convincing that a person walking back and forth from the left corner to the right corner appears to grow or shrink.
Some married couples perceive less distortion on their spouse than on strangers. This is a type of selective perceptual distortion known as the Honi phenomenon. The effect should be related to the strength of love, liking, and trust of the spouse being viewed.