Triangular bipyramid
Appearance
The triangular dipyramid is a polyhedron made entirely out of 6 faces, which are all equilateral triangles, 9 edges, and 5 vertexes. It is a convex deltahedron. Although all faces are congruent, it is not a Platonic solid because some vertexes have 3 triangles met at a point and others have 4.