Blend of 2 pentagonal pyramids

The , or ifbah, is an orbiform polyhedron. It consists of 6 triangles and 2 pentagons. It is a faceting of the icosahedron, and as its name suggests, it can be formed by blending two pentagonal pyramids together such that they share an edge and the two faces adjacent to this edge.

It appears as a cell of the dodecahedral extended double antiprism.

Vertex coordinates
The vertices of a of edge length 1 are:


 * $$\left(\pm\frac{1+\sqrt{5}}{4},\,0,\,\pm\frac{1}{2}\right),$$
 * $$\left(\pm\frac{1}{2},\,\frac{1+\sqrt{5}}{4},\,0\right),$$
 * $$\left(0,\,\frac{1}{2},\,\pm\frac{1+\sqrt{5}}{4}\right).$$