For all polyhedra the number of edges is two less ... A hexagonal prism has two hexagonal end faces. 6 × 2 = 12. A hexagonal prism has 12 vertices. A pyramid has one more face than the number ...

Besides the regular and semiregular solids, there are just ninety-two other convex polyhedra with regular faces. In 1966, the American mathematician Norman W. Johnson, a student of H.S.M. Coxeter at ...