Hopefully you have something like this:

A regular polyhedron is a polyhedron whose faces are congruent regular polygons which are assembled in the same way around each corner.

We will be only interested in _convex_ polyhedrons. A convex object is one such that whenever a line segment's end points are in the object, the entire line segment is in the object.



Although mathematicians talk about regular convex polyhedrons, it can be proved that every regular polyhedron is convex, so in fact we do not need to require the solid to be convex. Can you think how you might prove this?