Tetragonal disphenoid honeycomb

Tetragonal disphenoid tetrahedral honeycomb
File:Quartercell honeycomb.png
Type	convex uniform honeycomb dual
Coxeter-Dynkin diagram	Template:CDD
Cell type	File:Oblate tetrahedrille cell.png Tetragonal disphenoid
Face types	isosceles triangle {3}
Vertex figure	File:Tetrakishexahedron.jpg tetrakis hexahedron Template:CDD
Space group	Im3m (229)
Symmetry	[[4, 3, 4]]
Coxeter group	${\tilde{C}}_3$, [4, 3, 4]
Dual	Bitruncated cubic honeycomb
Properties	cell-transitive, face-transitive, vertex-transitive

The tetragonal disphenoid tetrahedral honeycomb is a space-filling tessellation (or honeycomb) in Euclidean 3-space made up of identical tetragonal disphenoidal cells. Cells are face-transitive with 4 identical isosceles triangle faces. John Horton Conway calls it an oblate tetrahedrille or shortened to obtetrahedrille.

A cell can be seen as 1/12 of a translational cube, with its vertices centered on two faces and two edges. Four of its edges belong to 6 cells, and two edges belong to 4 cells.

File:Oblate tetrahedrille cell.png

The tetrahedral disphenoid honeycomb is the dual of the uniform bitruncated cubic honeycomb.

Its vertices form the ATemplate:Sup sub / DTemplate:Sup sub lattice, which is also known as the body-centered cubic lattice.

Geometry

This honeycomb's vertex figure is a tetrakis cube: 24 disphenoids meet at each vertex. The union of these 24 disphenoids forms a rhombic dodecahedron. Each edge of the tessellation is surrounded by either four or six disphenoids, according to whether it forms the base or one of the sides of its adjacent isosceles triangle faces respectively. When an edge forms the base of its adjacent isosceles triangles, and is surrounded by four disphenoids, they form an irregular octahedron. When an edge forms one of the two equal sides of its adjacent isosceles triangle faces, the six disphenoids surrounding the edge form a special type of parallelepiped called a trigonal trapezohedron.

File:Disphenoid tetrah hc.png

An orientation of the tetragonal disphenoid honeycomb can be obtained by starting with a cubic honeycomb, subdividing it at the planes $x=y$, $x=z$, and $y=z$ (i.e. subdividing each cube into path-tetrahedra), then squashing it along the main diagonal until the distance between the points (0, 0, 0) and (1, 1, 1) becomes the same as the distance between the points (0, 0, 0) and (0, 0, 1).

Hexakis cubic honeycomb

Hexakis cubic honeycomb Pyramidille
File:Hexakis cubic honeycomb.png
Type	Dual uniform honeycomb
Coxeter–Dynkin diagrams	Template:CDD
Cell	Isosceles square pyramid File:Square pyramid.png
Faces	Triangle square
Space group Fibrifold notation	Pm3m (221) 4−:2
Coxeter group	${\tilde{C}}_3$, [4, 3, 4]
vertex figures	File:Hexahedron.pngFile:Rhombic dodecahedron.jpg Template:CDD, Template:CDD
Dual	Truncated cubic honeycomb
Properties	Cell-transitive

The hexakis cubic honeycomb is a uniform space-filling tessellation (or honeycomb) in Euclidean 3-space. John Horton Conway calls it a pyramidille.

Cells can be seen in a translational cube, using 4 vertices on one face, and the cube center. Edges are colored by how many cells are around each of them.

File:Cubic square pyramid.png

It can be seen as a cubic honeycomb with each cube subdivided by a center point into 6 square pyramid cells.

There are two types of planes of faces: one as a square tiling, and flattened triangular tiling with half of the triangles removed as holes.

Tiling plane	File:Square tiling uniform coloring 1.svg	File:Hexakis cubic honeycomb triangular plane.png
Symmetry	p4m, [4,4] (*442)	pmm, [∞,2,∞] (*2222)

Related honeycombs

It is dual to the truncated cubic honeycomb with octahedral and truncated cubic cells:

File:Truncated cubic honeycomb.png

If the square pyramids of the pyramidille are joined on their bases, another honeycomb is created with identical vertices and edges, called a square bipyramidal honeycomb, or the dual of the rectified cubic honeycomb.

It is analogous to the 2-dimensional tetrakis square tiling:

File:Tiling Dual Semiregular V4-8-8 Tetrakis Square.svg

Square bipyramidal honeycomb

Square bipyramidal honeycomb Oblate octahedrille
File:Hexakis cubic honeycomb.png
Type	Dual uniform honeycomb
Coxeter–Dynkin diagrams	Template:CDD
Cell	Square bipyramid File:Cubic square bipyramid.png
Faces	Triangles
Space group Fibrifold notation	Pm3m (221) 4−:2
Coxeter group	${\tilde{C}}_3$, [4,3,4]
vertex figures	File:Hexahedron.pngFile:Rhombic dodecahedron.jpg Template:CDD, Template:CDD
Dual	Rectified cubic honeycomb
Properties	Cell-transitive, Face-transitive

The square bipyramidal honeycomb is a uniform space-filling tessellation (or honeycomb) in Euclidean 3-space. John Horton Conway calls it an oblate octahedrille or shortened to oboctahedrille.

A cell can be seen positioned within a translational cube, with 4 vertices mid-edge and 2 vertices in opposite faces. Edges are colored and labeled by the number of cells around the edge.

File:Cubic square bipyramid.png

It can be seen as a cubic honeycomb with each cube subdivided by a center point into 6 square pyramid cells. The original cubic honeycomb walls are removed, joining pairs of square pyramids into square bipyramids (octahedra). Its vertex and edge framework is identical to the hexakis cubic honeycomb.

There is one type of plane with faces: a flattened triangular tiling with half of the triangles as holes. These cut face-diagonally through the original cubes. There are also square tiling plane that exist as nonface holes passing through the centers of the octahedral cells.

Tiling plane	File:Koushi 10x10.svg Square tiling "holes"	File:Square bipyramidal honeycomb triangular plane.png flattened triangular tiling
Symmetry	p4m, [4,4] (*442)	pmm, [∞,2,∞] (*2222)

Related honeycombs

It is dual to the rectified cubic honeycomb with octahedral and cuboctahedral cells:

File:Rectified cubic honeycomb.png

Phyllic disphenoidal honeycomb

Phyllic disphenoidal honeycomb Eighth pyramidille
(No image)
Type	Dual uniform honeycomb
Coxeter-Dynkin diagrams	Template:CDD
Cell	File:Half-turn tetrahedron diagram.png Phyllic disphenoid
Faces	Rhombus Triangle
Space group Fibrifold notation Coxeter notation	Im3m (229) 8o:2 [[4,3,4]]
Coxeter group	[4,3,4], ${\tilde{C}}_3$
vertex figures	File:Disdyakis dodecahedron.pngFile:Octagonal bipyramid.png Template:CDD, Template:CDD
Dual	Omnitruncated cubic honeycomb
Properties	Cell-transitive, face-transitive

The phyllic disphenoidal honeycomb is a uniform space-filling tessellation (or honeycomb) in Euclidean 3-space. John Horton Conway calls this an Eighth pyramidille.

A cell can be seen as 1/48 of a translational cube with vertices positioned: one corner, one edge center, one face center, and the cube center. The edge colors and labels specify how many cells exist around the edge. It is one 1/6 of a smaller cube, with 6 phyllic disphenoidal cells sharing a common diagonal axis.

File:Eighth pyramidille cell.png

Related honeycombs

It is dual to the omnitruncated cubic honeycomb:

File:Omnitruncated cubic honeycomb1.png

See also

• Architectonic and catoptric tessellation
• Cubic honeycomb
• Space frame
• Tetrahedral-octahedral honeycomb
• Triakis truncated tetrahedral honeycomb

References

• , reprinted in .
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