The commons ones that should come to mind are a tetrahedron, or regular triangular pyramid, and the cube. There is also a regular tetrahedron called an octahedron which has eight corners, each of which looks like the top of a square pyramid. There are two other regular polyhedron. If you've never seen them you probably wouldn't think them up on the spot, they are somewhat elaborate. One is called the dodecahedron, it has 12 sides, and the other is called the isocohedron, and it has 20 sides.



Are there anymore?