The cubic tegum, also called the cubic bipyramid, is a CRF polychoron with 12 square pyramids as cells. As the name suggests, it is a tegum based on the cube, formed by attaching 2 cubic pyramids together at their common base. It is unique among CRF tegums as the height from the top to the bottom vertex is identical to the cube's edge length.

Cubic tegum
Rank4
TypeCRF
Notation
Bowers style acronymCute
Coxeter diagramoxo4ooo3ooo&#xt
Bracket notation<[III]I>
Elements
Cells12 square pyramids
Faces24 triangles, 6 squares
Edges12+16
Vertices2+8
Vertex figures2 cubes, edge length 1
 8 skewed triangular tegums, based edge length 2, side edge length 1
Measures (edge length 1)
Inradius
Hypervolume
Dichoral anglesSquippy–3–squippy: 120°
 Squippy–4–squippy: 90°
Height1
Central density1
Related polytopes
DualSemi-uniform octahedral prism
ConjugateNone
Convex hullCubic tegum
Abstract & topological properties
Euler characteristic0
OrientableYes
Properties
SymmetryB3×A1, order 96
ConvexYes
NatureTame

A regular icositetrachoron can be decomposed into 8 CRF cubic tegums sharing one common vertex.

Gallery edit

Vertex coordinates edit

Coordinates for the vertices of a cubic tegum of edge length 1 are given by:

  •  
  •  

Representations edit

A cubic tegum has the following Coxeter diagrams:

  • oxo4ooo3ooo&#xt (full symmetry)
  • oxo oxo4ooo&#xt (square prismatic tegum)
  • oxo oxo oxo&#xt (cuboid tegum)
  • xo ox4oo3oo&#zx
  • oxo xox4ooo&#xt (square-first)
  • oxo xox xox&#xt (as above with rectangular symmetry)

Variations edit

The cubic tegum can have the heights of its pyramids varied while maintaining its full symmetry. These variants generally have 12 non-CRF square pyramids as cells.

One notable variation can be obtained as the dual of the uniform octahedral prism, which can be represented by m2o4o3m. In this variation the height between the top and bottom vertices of the tegum is   times the length of the edges of the base cube, and all the dichoral angles are  .

External links edit