# Truncated tetrahedral alterprism

Truncated tetrahedral alterprism
Rank4
TypeScaliform
Notation
Bowers style acronymTuta
Coxeter diagrams s4o3x ()
Elements
Cells
Faces
Edges12+24+24
Vertices24
Vertex figureSkew rectangular pyramid, base edge lengths 1 and 2, side edge lengths 1 and 3
Measures (edge length 1)
Circumradius${\displaystyle {\frac {\sqrt {6}}{2}}\approx 1.22475}$
Hypervolume${\displaystyle {\frac {7}{3}}\approx 2.33333}$
Dichoral anglesTet–3–tricu: 120°
Tricu–6–tut: 120°
Tricu–4–tricu: 90°
Tricu–3–tut: 60°
Height${\displaystyle {\frac {\sqrt {2}}{2}}\approx 0.70711}$
Central density1
Related polytopes
ArmyTuta
RegimentTuta
DualTriakis tetrahedral altertegum
ConjugateNone
Abstract & topological properties
Flag count768
Euler characteristic0
OrientableYes
Properties
Symmetry(A3×2×A1)/2, order 48
Flag orbits16
ConvexYes
NatureTame

The truncated tetrahedral alterprism or truncated tetrahedral cupoliprism, also known as the runcic snub cubic hosochoron, is a convex scaliform polychoron. It consists of two truncated tetrahedra as bases, joined by 8 triangular cupolas and 6 tetrahedra. 1 truncated tetrahedron, 1 tetrahedron, and 3 triangular cupolas join at each vertex. It can be formed by tetrahedrally alternating the small rhombicuboctahedral prism's triangles in such a way that the bases turn into truncated tetrahedra in opposite orientations.

It is also a convex segmentochoron (designated K-4.55 in Richard Klitzing's list), as truncated tetrahedron atop truncated tetrahedron.

The two truncated tetrahedra are in opposite orientation, so that the hexagonal faces of one base are parallel to the triangular faces of the other.

It can also be seen as a diminishing of the rectified tesseract, specifically one where two tetrahedron atop truncated tetrahedron caps are removed.

This polychoron was discovered in 2000 by Richard Klitzing while he was searching for convex segmentochora. After its discovery he came up with the concept of scaliform polytopes, so this polychoron can in fact be said to be the first non-uniform scaliform polytope discovered.

## Vertex coordinates

The vertices of a truncated tetrahedral alterprism of edge length 1, centered at the origin, are given by all even changes of sign, and all permutations in the first three coordinates of:

• ${\displaystyle \left({\frac {3{\sqrt {2}}}{4}},\,{\frac {\sqrt {2}}{4}},\,{\frac {\sqrt {2}}{4}},\,{\frac {\sqrt {2}}{4}}\right)}$.

## Representations

The truncated tetrahedral alterprism has the following Coxeter diagrams:

• s s4o3x () (as snub derivation)
• xo3xx3ox&#x (as segmentochoron)