Imagine playing a video game. As you press a button, figures and objects on the screen start moving around; they shift their position, they rotate, they zoom in or out. As you see this kind of motion, the video software must carry out quite a few computations. Such computations have been applied to the familiar face in Figure 6.1. These computations are implementations of affine maps, the subject of this chapter. Moving things around: affine maps in 20 applied to a familiar video game character.