For most people, the word “polyhedron” conjures up an image of a cube, a tetrahedron, or something similar—a solid figure with flat faces. If the polyhedron is regular, each face has the same size and ...

Consider what happens when a vertex of one tetrahedron pierces the face of a second tetrahedron to form a new, more complicated polyhedron. In the resulting geometric form, one triangular face has a ...

The net of a 3D shape is what it looks like if it is opened out flat. There are many types of nets for the different 3D shapes. A net is made from polygons that can be folded and joined to make a ...