Three dimensional space is easily imagined by looking at a corner of a rectangular room. The corner is called the origin. Each edge leaving from the origin (there are three of them) is called an axis. Each axis extends infinitely in two directions (up/down, left/right, and front/back).

Imagine laying long measuring sticks on each axis. These are used to locate specific points in space. On the Cubicomp, or any other graphics systems, the yardsticks are not infinitely long, and 3D space on these devices is not infinite; it is more like an aquarium.