A **regular polygon** is a polygon with both equal side lengths and vertex
angles.

**Regular polyhedra** are polygons with both identical regular faces and
equal face-to-face angles.

There are five regular polyhedra: tetrahedron, cube, octahedron, icosahedron, dodecahedron.

polyhedra |
vertices | edges | faces | |

tetrahedron |
4 | 6 | 4 | |

cube |
8 | 12 | 6 | |

octahedron |
6 | 12 | 8 | |

dodecahedron |
20 | 30 | 12 | |

icosahedron |
12 | 30 | 20 |