Trigonal trapezohedron is one of two special case of the "trigonal trapezohedron" with golden rhombus faces. The "acute" or "prolate" form has three acute angles corners of the rhombic faces meeting at two polar axis vertices. The "obtuse" or "oblate" or "flat" form has three obtuse angle corners of the rhombic faces meeting at the two polar axis vertices. The rhombic hexecontahedron can be constructed by 20 "acute golden rhombohedra" meeting at a point. A regular octahedron augumented by 2 regular tetrahedra creates a "trigonal trapezohedron", with coplanar equilateral triangles merged into 60-degree rhombic faces. Trigonal trapezohedron In geometry, a trigonal trapezohedron
Great dodecahedron pentagram, its two-dimensional analogue, via the extension of the ("n-1")-D pentagonal polytope faces of the core "n"D polytope (pentagons for the great dodecahedron, and line segments for the pentagram) until the figure again closes. It shares the same edge arrangement as the convex regular icosahedron; the compound with both is the small complex icosidodecahedron. If only the visible surface is considered, it has the same topology as a triakis icosahedron with concave pyramids rather than convex ones. The excavated dodecahedron can be seen as the same process applied to a regular dodecahedron. A truncation process applied to the great dodecahedron