A Prism is a Region which represents an extrusion of an existing Region
into one or more orthogonal dimensions (specified by another Region).
If the Region to be extruded has N axes, and the Region defining the
extrusion has M axes, then the resulting Prism will have (MN) axes.
A point is inside the Prism if the first N axis values correspond to
a point inside the Region being extruded, and the remaining M axis
values correspond to a point inside the Region defining the extrusion.
As an example, a cylinder can be represented by extruding an existing
Circle, using an Interval to define the extrusion. Ih this case, the
Interval would have a single axis and would specify the upper and
lower limits of the cylinder along its length.