ABSTRACT
Have you ever had the experience of viewing two dierent objects from one vantage point, concluding that they are identical, only to discover a er obtaining more information, that they are in fact vastly dierent? e example in Figure 22.1 illustrates this point succinctly. e object on the le is a cube, and the one in the center a cylinder. ey are poles apart from each other. Both objects look very dierent from the top, and yet from the front they look like the same square on the right.
