Convex uniform honeycomb
In geometry, a convex uniform honeycomb is a uniform tessellation which fills three-dimensional Euclidean space with non-overlapping convex uniform polyhedral cells.
Twenty-eight such honeycombs are known:
- the familiar cubic honeycomb and 7 truncations thereof;
- the alternated cubic honeycomb and 4 truncations thereof;
- 10 prismatic forms based on the uniform plane tilings ;
- 5 modifications of some of the above by elongation and/or gyration.
The Voronoi diagram of any lattice forms a convex uniform honeycomb in which the cells are zonohedra.
History
- 1900: Thorold Gosset enumerated the list of semiregular convex polytopes with regular cells in his publication On the Regular and Semi-Regular Figures in Space of n Dimensions, including one regular cubic honeycomb, and two semiregular forms with tetrahedra and octahedra.
- 1905: Alfredo Andreini enumerated 25 of these tessellations.
- 1991: Norman Johnson's manuscript Uniform Polytopes identified the list of 28.
- 1994: Branko Grünbaum, in his paper Uniform tilings of 3-space, also independently enumerated all 28, after discovering errors in Andreini's publication. He found the 1905 paper, which listed 25, had 1 wrong, and 4 being missing. Grünbaum states in this paper that Norman Johnson deserves priority for achieving the same enumeration in 1991. He also mentions that I. Alexeyev of Russia had contacted him regarding a putative enumeration of these forms, but that Grünbaum was unable to verify this at the time.
- 2006: George Olshevsky, in his manuscript Uniform Panoploid Tetracombs, along with repeating the derived list of 11 convex uniform tilings, and 28 convex uniform honeycombs, expands a further derived list of 143 convex uniform tetracombs.
- three of the five Platonic solids,
- six of the thirteen Archimedean solids, and
- five of the infinite family of prisms.
Names
The individual honeycombs are listed with names given to them by Norman Johnson.
For cross-referencing, they are given with list indices from Andreini, Williams, Johnson, and Grünbaum. Coxeter uses δ4 for a cubic honeycomb, hδ4 for an alternated cubic honeycomb, qδ4 for a quarter cubic honeycomb, with subscripts for other forms based on the ring patterns of the Coxeter diagram.
Compact Euclidean uniform tessellations (by their infinite Coxeter group families)
The fundamental infinite Coxeter groups for 3-space are:- The, , cubic,
- The, , alternated cubic,
- The cyclic group, or ],
In addition there are 5 special honeycombs which don't have pure reflectional symmetry and are constructed from reflectional forms with elongation and gyration operations.
The total unique honeycombs above are 18.
The prismatic stacks from infinite Coxeter groups for 3-space are:
- The ×, prismatic group,
- The ×, prismatic group,
- The ×, prismatic group,
- The ××, prismatic group,
The total unique prismatic honeycombs above are 10.
Combining these counts, 18 and 10 gives us the total 28 uniform honeycombs.
The C~3, 4,3,4 group (cubic)
The regular cubic honeycomb, represented by Schläfli symbol, offers seven unique derived uniform honeycombs via truncation operations. The reflectional symmetry is the affine Coxeter group . There are four index 2 subgroups that generate alternations: , , , and +, with the first two generated repeated forms, and the last two are nonuniform.B~3, 4,31,1 group
The, group offers 11 derived forms via truncation operations, four being unique uniform honeycombs. There are 3 index 2 subgroups that generate alternations: , , and +. The first generates repeated honeycomb, and the last two are nonuniform but included for completeness.The honeycombs from this group are called alternated cubic because the first form can be seen as a cubic honeycomb with alternate vertices removed, reducing cubic cells to tetrahedra and creating octahedron cells in the gaps.
Nodes are indexed left to right as 0,1,0',3 with 0' being below and interchangeable with 0. The alternate cubic names given are based on this ordering.
A~3, 3[4)] group
There are 5 forms constructed from the, ] Coxeter group, of which only the quarter cubic honeycomb is unique. There is one index 2 subgroup ]+ which generates the snub form, which is not uniform, but included for completeness.Nonwythoffian forms (gyrated and elongated)
Three more uniform honeycombs are generated by breaking one or another of the above honeycombs where its faces form a continuous plane, then rotating alternate layers by 60 or 90 degrees and/or inserting a layer of prisms.The elongated and gyroelongated alternated cubic tilings have the same vertex figure, but are not alike. In the elongated form, each prism meets a tetrahedron at one triangular end and an octahedron at the other. In the gyroelongated form, prisms that meet tetrahedra at both ends alternate with prisms that meet octahedra at both ends.
The gyroelongated triangular prismatic tiling has the same vertex figure as one of the plain prismatic tilings; the two may be derived from the gyrated and plain triangular prismatic tilings, respectively, by inserting layers of cubes.
Referenced indices | symbol | Honeycomb name | cell types | Solids | Frames | vertex figure |
J52 A2' G2 O22 | h:g | gyrated alternated cubic | tetrahedron octahedron | triangular orthobicupola | ||
J61 A? G3 O24 | h:ge | gyroelongated alternated cubic | triangular prism tetrahedron octahedron | |||
J62 A? G4 O23 | h:e | elongated alternated cubic | triangular prism tetrahedron octahedron | |||
J63 A? G12 O12 | :g × | gyrated triangular prismatic | triangular prism | |||
J64 A? G15 O13 | :ge × | gyroelongated triangular prismatic | triangular prism cube |
Prismatic stacks
Eleven prismatic tilings are obtained by stacking the eleven uniform plane tilings, shown below, in parallel layers. The vertex figure of each is an irregular bipyramid whose faces are isosceles triangles.The C~2×I~1(∞), 4,4,2,∞, prismatic group
There are only 3 unique honeycombs from the square tiling, but all 6 tiling truncations are listed below for completeness, and tiling images are shown by colors corresponding to each form.Indices | Coxeter-Dynkin and Schläfli symbols | Honeycomb name | Plane tiling | Solids | Tiling |
J11,15 A1 G22 | × | Cubic | |||
J11,15 A1 G22 | r× | Cubic | |||
J11,15 A1 G22 | rr× | Cubic | |||
J45 A6 G24 | t× | Truncated/Bitruncated square prismatic | |||
J45 A6 G24 | tr× | Truncated/Bitruncated square prismatic | |||
J44 A11 G14 | sr× | Snub square prismatic | |||
Nonuniform | ht0,1,2,3 |
The G~2xI~1(∞), 6,3,2,∞ prismatic group
Enumeration of Wythoff forms
All nonprismatic Wythoff constructions by Coxeter groups are given below, along with their alternations. Uniform solutions are indexed with Branko Grünbaum's listing. Green backgrounds are shown on repeated honeycombs, with the relations are expressed in the extended symmetry diagrams.Examples
All 28 of these tessellations are found in crystal arrangements.The alternated cubic honeycomb is of special importance since its vertices form a cubic close-packing of spheres. The space-filling truss of packed octahedra and tetrahedra was apparently first discovered by Alexander Graham Bell and independently re-discovered by Buckminster Fuller.
. Octet trusses are now among the most common types of truss used in construction.
Frieze forms
If cells are allowed to be uniform tilings, more uniform honeycombs can be defined:Families:
- x: Cubic slab honeycombs
- x: Tri-hexagonal slab honeycombs
- x: Triangular slab honeycombs
- xx: = Cubic column honeycombs
- x: Polygonal column honeycombs
- xx: = - =
Cubic slab honeycomb | Alternated hexagonal slab honeycomb | Trihexagonal slab honeycomb |
43: cube 44: square tiling | 33: tetrahedron 34: octahedron 36: hexagonal tiling | 3.4.4: triangular prism 4.4.6: hexagonal prism 2: trihexagonal tiling |
Scaliform honeycomb
A scaliform honeycomb is vertex-transitive, like a uniform honeycomb, with regular polygon faces while cells and higher elements are only required to be orbiforms, equilateral, with their vertices lying on hyperspheres. For 3D honeycombs, this allows a subset of Johnson solids along with the uniform polyhedra. Some scaliforms can be generated by an alternation process, leaving, for example, pyramid and cupola gaps.Hyperbolic forms
There are 9 Coxeter group families of compact uniform honeycombs in hyperbolic 3-space, generated as Wythoff constructions, and represented by ring permutations of the Coxeter-Dynkin diagrams for each family.From these 9 families, there are a total of 76 unique honeycombs generated:
- : - 9 forms
- : - 15 forms
- : - 9 forms
- : - 11 forms
- : - 9 forms
- : - 6 forms
- : - 9 forms
- : - 9 forms
- : - 6 forms
Paracompact hyperbolic forms
There are also 23 paracompact Coxeter groups of rank 4. These families can produce uniform honeycombs with unbounded facets or vertex figure, including ideal vertices at infinity:Type | Coxeter groups | Unique honeycomb count |
Linear graphs | 4×15+6+8+8 = 82 | |
Tridental graphs | 4+4+0 = 8 | |
Cyclic graphs | 4×9+5+1+4+1+0 = 47 | |
Loop-n-tail graphs | 4+4+4+2 = 14 |