a) Have you ever seen a painting done on a saw-tooth contoured surface instead of a flat surface? I forget if the end-effect is a 3-D trick on the eye, or what. As I recall, each subsequent left surface of the sawtooth has a bit of an overall image on it, although each one is slighty different than the last. The same is true with the right side of each saw tooth. Thus, you see different views in the overall picture depending where you stand.
Or, (b) If you are unfamiliar with this art, any suggestions on how to google for something one can only loosely describe? I recall stumbling upon this while surfing the web once, but I have no clue how to begin to google on this.