A 3D shape with all straight edges and flat faces is a polyhedron. Other 3D shapes with least one curved surface are not polyhedra. A 3D shape with regular polygonal faces, meeting at equal angles, is ...

A pyramid is a 3D shape with a flat base, and triangular edges that meet at a point. The base of the pyramid can be any polygon. A glass sculpture in the shape of a square based pyramid is to be made.