"In other words, the Great Pyramid is a concave octagonal pyramid, rather than the standard square pyramid," he added ...

A tetrahedron is a triangular pyramid with all equilateral triangle faces. A pyramid with a square base is a square-based pyramid. Image caption, 3D shapes that are non-polyhedral include ...

This was a kiln-er find. Puppets with remarkable facial features believed to date back some 2,400 years have been discovered at the top of an ancient pyramid in the jungle of El Salvador.

Zalgaller offered a computer-based computational proof that Johnson had completed the enumeration of convex polyhedra with regular faces. National Museum of American History Polyhedron Model by Martin ...

Right, what about triangles? Triangles become pyramids. You're now a square based pyramid with 4 triangular faces and a square face for your bottom. You can get pyramids with different shaped bases.