Blend of 2 pentagonal pyramids

Blend of 2 pentagonal pyramids
(OFF file)
Rank	3
Type	Orbiform
Space	Spherical
Notation
Bowers style acronym	Ifbah
Elements
Faces	2+4 triangles, 2 pentagons
Edges	2+4+4+4
Vertices	2+2+4
Measures (edge length 1)
Circumradius	$\sqrt{\frac{5+\sqrt{5}}{8}} \approx 0.95106$
Number of external pieces	10
Level of complexity	16
Related polytopes
Conjugate	Blend of 2 pentagrammic pyramids
Abstract & topological properties
Flag count	56
Euler characteristic	2
Orientable	Yes
Genus	0
Properties
Symmetry	K2×I, order 4
Convex	No
Nature	Tame

The blend of 2 pentagonal pyramids, 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 blend of 2 pentagonal pyramids of edge length 1 are:

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

Gallery

External links

• Klitzing, Richard. "ifbah".

• Bowers, Jonathan. "Batch 2: Ike and Sissid Facetings" (#16 under ike).