Heptahedron

Description

A convex heptahedron with rotational symmetry of order 3. It has 12 edges, 9 of which have right dihedral angles, and the remaining three have dihedral angles of 135°. These three edges are all orthogonal to each other. Joining one of these to its mirror image on one of the quadrilateral faces, and adding a prism, gives the [decahedron](https://sketchfab.com/3d-models/decahedron-e7b22b7e08084351acf1987243f045ab).