Rhombic dodecahedral honeycomb

Rhombic dodecahedral honeycomb
Typeconvex uniform honeycomb dual
Coxeter-Dynkin diagram =
Cell type
Rhombic dodecahedron V3.4.3.4
Face typesRhombus
Space groupFm3m (225)
Coxeter notation½, [1+,4,3,4]
, [4,31,1]
×2, <[3[4]]>
Dualtetrahedral-octahedral honeycomb
Propertiesedge-transitive, face-transitive, cell-transitive

The rhombic dodecahedral honeycomb is a space-filling tessellation (or honeycomb) in Euclidean 3-space. It is the Voronoi diagram of the face-centered cubic sphere-packing, which has the densest possible packing of equal spheres in ordinary space (see Kepler conjecture).

Geometry

It consists of copies of a single cell, the rhombic dodecahedron. All faces are rhombi, with diagonals in the ratio 1:2. Three cells meet at each edge. The honeycomb is thus cell-transitive, face-transitive and edge-transitive; but it is not vertex-transitive, as it has two kinds of vertex. The vertices with the obtuse rhombic face angles have 4 cells. The vertices with the acute rhombic face angles have 6 cells.

The rhombic dodecahedron can be twisted on one of its hexagonal cross-sections to form a trapezo-rhombic dodecahedron, which is the cell of a somewhat similar tessellation, the Voronoi diagram of hexagonal close-packing.

Trapezo-rhombic dodecahedral honeycomb

Trapezo-rhombic dodecahedral honeycomb
Typeconvex uniform honeycomb dual
Cell typetrapezo-rhombic dodecahedron VG3.4.3.4
Face typesrhombus,
trapezoid
Symmetry groupP63/mmc
Dualgyrated tetrahedral-octahedral honeycomb
Propertiesedge-uniform, face-uniform, cell-uniform

The trapezo-rhombic dodecahedral honeycomb is a space-filling tessellation (or honeycomb) in Euclidean 3-space. It consists of copies of a single cell, the trapezo-rhombic dodecahedron. It is similar to the higher symmetric rhombic dodecahedral honeycomb which has all 12 faces as rhombi.

It is a dual to the vertex-transitive gyrated tetrahedral-octahedral honeycomb.

Rhombic pyramidal honeycomb

Rhombic pyramidal honeycomb
(No image)
TypeDual uniform honeycomb
Coxeter-Dynkin diagrams
Cell
rhombic pyramid
Faces Rhombus
Triangle
Coxeter groups[4,31,1],
[3[4]],
Symmetry groupFm3m (225)
vertex figures
, ,
DualCantic cubic honeycomb
PropertiesCell-transitive

The rhombic pyramidal honeycomb is a uniform space-filling tessellation (or honeycomb) in Euclidean 3-space. John Horton Conway calls it a truncated tetraoctahedrille.

It is dual to the cantic cubic honeycomb:

References

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