A deltahedron (plural deltahedra)'s a polyhedron whose faces are all equilateral triangles. The name's taken from the Greek majuscule delta (Δ), which has the shape of an equilateral triangle. There're infinitely many deltahedra, but of these only eight are convex, having 4, 6, 8, 10, 12, 14, 16 and 20 faces. The number of faces, edges, and vertices's listed below for each of the eight convex deltahedra. The deltahedra shouldn't be confused with the deltohedra (spelled with an "o"), polyhed… (More on Deltahedron)