1. They are all 3D; they all consist of vertices, edges, and faces (an edge is where two faces meet, and a vertex is a corner (where three or more faces meet)); and they all have only flat surfaces. These shapes are examples of polyhedra. A polyhedron (pl. polyhedra) is a special kind of 3D object. It has faces, vertices and edges. All of its faces are flat surfaces. Pyramids [[[[Insert Link to definition from grade 2, 3, or 4.]]]] and prisms [[[[Insert Link to definition from grade 2, 3, or 4.]]]] are two of many examples of polyhedra. Below are some pictures of polyhedra as they occur in the world.

hexagonal prisms
pentagonal prisms

Giza Plateau