Pinball games were constrained by physical limitations, ultimately by the physical laws that govern the motion of a small metal ball. The video world knows no such bounds. Objects fly, spin, accelerate, change shape and color, disappear and reappear. Their behavior, like the behavior of anything created by a computer program, is limited only by the programmer's imagination. The objects in a video game are representations of objects. And a representation of a ball, unlike a real one, never need obey the laws of gravity unless its programmer wants it to.

Pinball games were constrained by physical limitations, ultimately by the physical laws that govern the motion of a small metal ball. The video world knows no such bounds. Objects fly, spin, accelerate, change shape and color, disappear and reappear. Their behavior, like the behavior of anything created by a computer program, is limited only by the programmer's imagination. The objects in a video game are representations of objects. And a representation of a ball, unlike a real one, never need obey the laws of gravity unless its programmer wants it to.