Definition of Terms, Continued
Spheres are formed by a circle revolving around its diameter. The diameter
of the circle then becomes the axis and the ends of the axis are known as
Figure 2-15 shows a sphere, its axis, and its poles.
A torus or toroid is formed by a circle or curve revolving around but not
intersecting or containing an axis in its own plane.
The axis of a torus is
eccentric to the diameter of the circle or curve.
Figure 2-16 is an example of a torus.
Figure 2-16.A torus.
Continued on next page