Uniform tiling

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In geometry, a uniform tiling is a tessellation of the plane by regular polygon faces with the restriction of being vertex-transitive.

Uniform tilings can exist in both the Euclidean plane and hyperbolic plane. Uniform tilings are related to the finite uniform polyhedra which can be considered uniform tilings of the sphere.

Most uniform tilings can be made from a Wythoff construction starting with a symmetry group and a singular generator point inside of the fundamental domain. A planar symmetry group has a polygonal fundamental domain and can be represented by the group name represented by the order of the mirrors in sequential vertices.

A fundamental domain triangle is (p q r), and a right triangle (p q 2), where p, q, r are whole numbers greater than 1. The triangle may exist as a spherical triangle, a Euclidean plane triangle, or a hyperbolic plane triangle, depending on the values of p, q and r.

There are a number of symbolic schemes for naming these figures, from a modified Schläfli symbol for right triangle domains: (p q 2) → {p, q}. The Coxeter-Dynkin diagram is a triangular graph with p, q, r labeled on the edges. If r = 2, the graph is linear since order-2 domain nodes generate no reflections. The Wythoff symbol takes the 3 integers and separates them by a vertical bar (|). If the generator point is off the mirror opposite a domain node, it is given before the bar.

Finally tilings can be described by their vertex configuration, the sequence of polygons around each vertex.

All uniform tilings can be constructed from various operations applied to regular tilings. These operations as named by Norman Johnson are called truncation (cutting vertices), rectification (cutting vertices until edges disappear), and Cantellation (cutting edges). Omnitruncation is an operation that combines truncation and cantellation. Snubbing is an operation of Alternate truncation of the omnitruncated form. (See Uniform polyhedron#Wythoff construction operators for more details.)

Coxeter groups

Coxeter groups for the plane define the Wythoff construction and can be represented by Coxeter-Dynkin diagrams:

For groups with whole number orders, including:

Euclidean plane
Orbifold
symmetry		 Coxeter group Coxeter
diagram		 notes
Compact
*333 (3 3 3) {\tilde{A}}_2 [3[3]] CDel node.pngCDel split1.pngCDel branch.png 3 reflective forms, 1 snub
*442 (4 4 2) {\tilde{B}}_2 [4,4] CDel node.pngCDel 4.pngCDel node.pngCDel 4.pngCDel node.png 5 reflective forms, 1 snub
*632 (6 3 2) {\tilde{G}}_2 [6,3] CDel node.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node.png 7 reflective forms, 1 snub
*2222 (∞ 2 ∞ 2) {\tilde{I}}_1 × {\tilde{I}}_1 [∞,2,∞] CDel node.pngCDel infin.pngCDel node.pngCDel 2.pngCDel node.pngCDel infin.pngCDel node.png 3 reflective forms, 1 snub
Noncompact (frieze)
*∞∞ (∞) {\tilde{I}}_1 [∞] CDel node.pngCDel infin.pngCDel node.png
*22∞ (2 2 ∞) {\tilde{I}}_1 × {\tilde{A}}_2 [∞,2] CDel node.pngCDel infin.pngCDel node.pngCDel 2.pngCDel node.png 2 reflective forms, 1 snub
Hyperbolic plane
Orbifold
symmetry		 Coxeter group Coxeter
diagram		 notes
Compact
*pq2 (p q 2) [p,q] CDel node.pngCDel p.pngCDel node.pngCDel q.pngCDel node.png 2(p+q) < pq
*pqr (p q r) [(p,q,r)] CDel 3.pngCDel node.pngCDel p.pngCDel node.pngCDel q.pngCDel node.pngCDel r.png pq+pr+qr < pqr
Paracompact
*∞p2 (p ∞ 2) [p,∞] CDel node.pngCDel p.pngCDel node.pngCDel infin.pngCDel node.png p>=3
*∞pq (p q ∞) [(p,q,∞)] CDel 3.pngCDel node.pngCDel p.pngCDel node.pngCDel q.pngCDel node.pngCDel infin.png p,q>=3, p+q>6
*∞∞p (p ∞ ∞) [(p,∞,∞)] CDel 3.pngCDel node.pngCDel p.pngCDel node.pngCDel infin.pngCDel node.pngCDel infin.png p>=3
*∞∞∞ (∞ ∞ ∞) [(∞,∞,∞)] CDel 3.pngCDel node.pngCDel infin.pngCDel node.pngCDel infin.pngCDel node.pngCDel infin.png

Uniform tilings of the Euclidean plane

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There are symmetry groups on the Euclidean plane constructed from fundamental triangles: (4 4 2), (6 3 2), and (3 3 3). Each is represented by a set of lines of reflection that divide the plane into fundamental triangles.

These symmetry groups create 3 regular tilings, and 7 semiregular ones. A number of the semiregular tilings are repeated from different symmetry constructors.

A prismatic symmetry group represented by (2 2 2 2) represents by two sets of parallel mirrors, which in general can have a rectangular fundamental domain. It generates no new tilings.

A further prismatic symmetry group represented by (∞ 2 2) which has an infinite fundamental domain. It constructs two uniform tilings, the apeirogonal prism and apeirogonal antiprism.

The stacking of the finite faces of these two prismatic tilings constructs one non-Wythoffian uniform tiling of the plane. It is called the elongated triangular tiling, composed of alternating layers of squares and triangles.

Right angle fundamental triangles: (p q 2)

(p q 2) Fund.
triangles		 Parent Truncated Rectified Bitruncated Birectified
(dual)		 Cantellated Omnitruncated
(Cantitruncated)		 Snub
Wythoff symbol q | p 2 2 q | p 2 | p q 2 p | q p | q 2 p q | 2 p q 2 | | p q 2
Schläfli symbol t{p,q} t{p,q} r{p,q} 2t{p,q}=t{q,p} 2r{p,q}={q,p} rr{p,q} tr{p,q} sr{p,q}
Coxeter diagram CDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node.png CDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.png CDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.png CDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.png CDel node.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.png CDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.png CDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.png CDel node h.pngCDel p.pngCDel node h.pngCDel q.pngCDel node h.png
Vertex config. pq q.2p.2p (p.q)2 p.2q.2q qp p.4.q.4 4.2p.2q 3.3.p.3.q
Square tiling
(4 4 2)		 Tiling Dual Semiregular V4-8-8 Tetrakis Square-2-color-zoom.svg Uniform tiling 44-t0.png
{4,4}		 Uniform tiling 44-t01.png
4.8.8		 Uniform tiling 44-t1.png
4.4.4.4		 Uniform tiling 44-t12.png
4.8.8		 Uniform tiling 44-t2.png
{4,4}		 Uniform tiling 44-t02.png
4.4.4.4		 Uniform tiling 44-t012.png
4.8.8		 Uniform tiling 44-snub.png
3.3.4.3.4
Hexagonal tiling
(6 3 2)		 Tile V46b.svg Uniform tiling 63-t0.png
{6,3}		 Uniform tiling 63-t01.png
3.12.12		 Uniform tiling 63-t1.png
3.6.3.6		 Uniform tiling 63-t12.png
6.6.6		 Uniform tiling 63-t2.png
{3,6}		 Uniform tiling 63-t02.png
3.4.6.4		 Uniform tiling 63-t012.png
4.6.12		 Uniform tiling 63-snub.png
3.3.3.3.6

General fundamental triangles: (p q r)

Wythoff symbol
(p q r)		 Fund.
triangles		 q | p r r q | p r | p q r p | q p | q r p q | r p q r | | p q r
Coxeter diagram CDel 3.pngCDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node.pngCDel r.png CDel 3.pngCDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.pngCDel r.png CDel 3.pngCDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.pngCDel r.png CDel 3.pngCDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.pngCDel r.png CDel 3.pngCDel node.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.pngCDel r.png CDel 3.pngCDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.pngCDel r.png CDel 3.pngCDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.pngCDel r.png CDel 3.pngCDel node h.pngCDel p.pngCDel node h.pngCDel q.pngCDel node h.pngCDel r.png
Vertex config. (p.q)r r.2p.q.2p (p.r)q q.2r.p.2r (q.r)p q.2r.p.2r r.2q.p.2q 3.r.3.q.3.p
Triangular
(3 3 3)		 Tiling Regular 3-6 Triangular.svg Uniform tiling 333-t0.png
(3.3)3		 Uniform tiling 333-t01.png
3.6.3.6		 Uniform tiling 333-t1.png
(3.3)3		 Uniform tiling 333-t12.png
3.6.3.6		 Uniform tiling 333-t2.png
(3.3)3		 Uniform tiling 333-t02.png
3.6.3.6		 Uniform tiling 333-t012.png
6.6.6		 Uniform tiling 333-snub.png
3.3.3.3.3.3

Non-simplical fundamental domains

The only possible fundamental domain in Euclidean 2-space that is not a simplex is the rectangle (∞ 2 ∞ 2), with Coxeter diagram: CDel node.pngCDel infin.pngCDel node.pngCDel 2.pngCDel node.pngCDel infin.pngCDel node.png. All forms generated from it become a square tiling.

Uniform tilings of the hyperbolic plane

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There are infinitely many uniform tilings of convex regular polygons on the hyperbolic plane, each based on a different reflective symmetry group (p q r).

A sampling is shown here with a Poincaré disk projection.

The Coxeter-Dynkin diagram is given in a linear form, although it is actually a triangle, with the trailing segment r connecting to the first node.

Further symmetry groups exist in the hyperbolic plane with quadrilateral fundamental domains starting with (2 2 2 3), etc., that can generate new forms. As well there's fundamental domains that place vertices at infinity, such as (∞ 2 3), etc.

Right angle fundamental triangles: (p q 2)

(p q 2) Fund.
triangles		 Parent Truncated Rectified Bitruncated Birectified
(dual)		 Cantellated Omnitruncated
(Cantitruncated)		 Snub
Wythoff symbol q | p 2 2 q | p 2 | p q 2 p | q p | q 2 p q | 2 p q 2 | | p q 2
Schläfli symbol t{p,q} t{p,q} r{p,q} 2t{p,q}=t{q,p} 2r{p,q}={q,p} rr{p,q} tr{p,q} sr{p,q}
Coxeter-Dynkin diagram CDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node.png CDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.png CDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.png CDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.png CDel node.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.png CDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.png CDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.png CDel node h.pngCDel p.pngCDel node h.pngCDel q.pngCDel node h.png
Vertex figure pq (q.2p.2p) (p.q.p.q) (p. 2q.2q) qp (p. 4.q.4) (4.2p.2q) (3.3.p. 3.q)
(Hyperbolic plane)
(5 4 2)		 Order-4 bisected pentagonal tiling.png
V4.8.10		 Uniform tiling 54-t0.png
{5,4}		 Uniform tiling 54-t01.png
4.10.10		 Uniform tiling 54-t1.png
4.5.4.5		 Uniform tiling 54-t12.png
5.8.8		 Uniform tiling 54-t2.png
{4,5}		 Uniform tiling 54-t02.png
4.4.5.4		 Uniform tiling 54-t012.png
4.8.10		 Uniform tiling 54-snub.png
3.3.4.3.5
(Hyperbolic plane)
(5 5 2)		 72px
V4.10.10		 Uniform tiling 552-t0.png
{5,5}		 Uniform tiling 552-t01.png
5.10.10		 Uniform tiling 552-t1.png
5.5.5.5		 Uniform tiling 552-t12.png
5.10.10		 Uniform tiling 552-t2.png
{5,5}		 Uniform tiling 552-t02.png
5.4.5.4		 Uniform tiling 552-t012.png
4.10.10		 Uniform tiling 552-snub.png
3.3.5.3.5
(Hyperbolic plane)
(7 3 2)		 Order-3 heptakis heptagonal tiling.png
V4.6.14		 Uniform tiling 73-t0.png
{7,3}		 Uniform tiling 73-t01.png
3.14.14		 Uniform tiling 73-t1.png
3.7.3.7		 Uniform tiling 73-t12.png
7.6.6		 Uniform tiling 73-t2.png
{3,7}		 Uniform tiling 73-t02.png
3.4.7.4		 Uniform tiling 73-t012.png
4.6.14		 Uniform tiling 73-snub.png
3.3.3.3.7
(Hyperbolic plane)
(8 3 2)		 Order-3 octakis octagonal tiling.png
V4.6.16		 Uniform tiling 83-t0.png
{8,3}		 Uniform tiling 83-t01.png
3.16.16		 Uniform tiling 83-t1.png
3.8.3.8		 Uniform tiling 83-t12.png
8.6.6		 Uniform tiling 83-t2.png
{3,8}		 Uniform tiling 83-t02.png
3.4.8.4		 Uniform tiling 83-t012.png
4.6.16		 Uniform tiling 83-snub.png
3.3.3.3.8

General fundamental triangles (p q r)

Wythoff symbol
(p q r)		 Fund.
triangles		 q | p r r q | p r | p q r p | q p | q r p q | r p q r | | p q r
Coxeter-Dynkin diagram CDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node.pngCDel r.png CDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.pngCDel r.png CDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node.pngCDel r.png CDel node.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.pngCDel r.png CDel node.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.pngCDel r.png CDel node 1.pngCDel p.pngCDel node.pngCDel q.pngCDel node 1.pngCDel r.png CDel node 1.pngCDel p.pngCDel node 1.pngCDel q.pngCDel node 1.pngCDel r.png CDel node h.pngCDel p.pngCDel node h.pngCDel q.pngCDel node h.pngCDel r.png
Vertex figure (p.r)q (r.2p.q.2p) (p.q)r (q.2r.p. 2r) (q.r)p (r.2q.p. 2q) (2p.2q.2r) (3.r.3.q.3.p)
Hyperbolic
(4 3 3)		 Uniform dual tiling 433-t012.png
V6.6.8		 Uniform tiling 433-t0.png
(3.4)3		 Uniform tiling 433-t01.png
3.8.3.8		 Uniform tiling 433-t1.png
(3.4)3		 Uniform tiling 433-t12.png
3.6.4.6		 Uniform tiling 433-t2.png
(3.3)4		 Uniform tiling 433-t02.png
3.6.4.6		 Uniform tiling 433-t012.png
6.6.8		 Uniform tiling 433-snub2.png
3.3.3.3.3.4
Hyperbolic
(4 4 3)		 72px
V6.8.8		 Uniform tiling 443-t0.png
(3.4)4		 Uniform tiling 443-t01.png
3.8.4.8		 Uniform tiling 443-t1.png
(4.4)3		 Uniform tiling 443-t12.png
3.6.4.6		 Uniform tiling 443-t2.png
(3.4)4		 Uniform tiling 443-t02.png
4.6.4.6		 Uniform tiling 443-t012.png
6.8.8		 Uniform tiling 443-snub1.png
3.3.3.4.3.4
Hyperbolic
(4 4 4)		 72px
V8.8.8		 Uniform tiling 444-t0.png
(4.4)4		 Uniform tiling 444-t01.png
4.8.4.8		 Uniform tiling 444-t1.png
(4.4)4		 Uniform tiling 444-t12.png
4.8.4.8		 Uniform tiling 444-t2.png
(4.4)4		 Uniform tiling 444-t02.png
4.8.4.8		 Uniform tiling 444-t012.png
8.8.8		 Uniform tiling 444-snub.png
3.4.3.4.3.4

Expanded lists of uniform tilings

There are a number ways the list of uniform tilings can be expanded:

  1. Vertex figures can have retrograde faces and turn around the vertex more than once.
  2. Star polygons tiles can be included.
  3. Apeirogons, {∞}, can be used as tiling faces.
  4. The restriction that tiles meet edge-to-edge can be relaxed, allowing additional tilings such as the Pythagorean tiling.

Symmetry group triangles with retrogrades include:

(4/3 4/3 2) (6 3/2 2) (6/5 3 2) (6 6/5 3) (6 6 3/2)

Symmetry group triangles with infinity include:

(4 4/3 ∞) (3/2 3 ∞) (6 6/5 ∞) (3 3/2 ∞)

Branko Grünbaum, in the 1987 book Tilings and patterns, in section 12.3 enumerates a list of 25 uniform tilings, including the 11 convex forms, and adds 14 more he calls hollow tilings which included the first two expansions above, star polygon faces and vertex figures.

H.S.M. Coxeter et al., in the 1954 paper 'Uniform polyhedra', in Table 8: Uniform Tessellations, uses the first three expansions and enumerates a total of 38 uniform tilings.

Finally, if a tiling made of 2 apeirogons is also counted, the total can be considered 39 uniform tilings.

File:Six uniform tiling vertex figures.png
The vertex figures for the six tilings with convex regular polygons and apeirogon faces.(The Wythoff symbol is given in red.)

The 7 new tilings with {∞} tiles, given by vertex figure and Wythoff symbol are:

  1. ∞.∞ (Two half-plane tiles, infinite dihedron)
  2. 4.4.∞ - ∞ 2 | 2 (Apeirogonal prism)
  3. 3.3.3.∞ - | 2 2 ∞ (Apeirogonal antiprism)
  4. 4.∞.4/3.∞ - 4/3 4 | ∞ (alternate square tiling)
  5. 3.∞.3.∞.3.∞ - 3/2 | 3 ∞ (alternate triangular tiling)
  6. 6.∞.6/5.∞ - 6/5 6 | ∞ (alternate trihexagonal tiling with only hexagons)
  7. ∞.3.∞.3/2 - 3/2 3 | ∞ (alternate trihexagonal tiling with only triangles)

The remaining list includes 21 tilings, 7 with {∞} tiles (apeirogons). Drawn as edge-graphs there are only 14 unique tilings, and the first is identical to the 3.4.6.4 tiling.

File:Twenty one uniform tiling vertex figures.png
Vertex figures for 21 uniform tilings.

The 21 grouped by shared edge graphs, given by vertex figures and Wythoff symbol, are:

Type Vertex
configuration		 Wythoff symbol
1 3/2.12.6.12 3/2 6 | 6
4.12.4/3.12/11 2 6 (3/2 3) |
2 8/3.4.8/3.∞ 4 ∞ | 4/3
8/3.8.8/5.8/7 4/3 4 (2 ∞) |
8.4/3.8.∞ 4/3 ∞ | 4
3 12/5.6.12/5.∞ 6 ∞ | 6/5
12/5.12.12/7.12/11 6/5 6 (3 ∞) |
12.6/5.12.∞ 6/5 ∞ | 6
4 12/5.3.12/5.6/5 3 6 | 6/5
12/5.4.12/7.4/3 2 6/5 (3/2 3) |
4.3/2.4.6/5 3/2 6 | 2
5 8.8/3.∞ 4/3 4 ∞ |
6 12.12/5.∞ 6/5 6 ∞ |
7 8.4/3.8/5 2 4/3 4 |
8 6.4/3.12/7 2 3 6/5 |
9 12.6/5.12/7 3 6/5 6 |
10 4.8/5.8/5 2 4 | 4/3
11 12/5.12/5.3/2 2 3 | 6/5
12 4.4.3/2.3/2.3/2 non-Wythoffian
13 4.3/2.4.3/2.3/2 | 2 4/3 4/3 (snub)
14 3.4.3.4/3.3.∞ | 4/3 4 ∞ (snub)

Self-dual tilings

The {4,4} square tiling (black) with its dual (red).

Tilings can also be self-dual. The square tiling, with Schlafli symbol {4,4}, is self-dual; shown here are two square tilings (red and black), dual to each other.

See also

References

External links

Fundamental convex regular and uniform honeycombs in dimensions 2–10
Family {\tilde{A}}_{n-1} {\tilde{C}}_{n-1} {\tilde{B}}_{n-1} {\tilde{D}}_{n-1} {\tilde{G}}_2 / {\tilde{F}}_4 / {\tilde{E}}_{n-1}
Uniform tiling {3[3]} δ3 hδ3 qδ3 Hexagonal
Uniform convex honeycomb {3[4]} δ4 hδ4 qδ4
Uniform 5-honeycomb {3[5]} δ5 hδ5 qδ5 24-cell honeycomb
Uniform 6-honeycomb {3[6]} δ6 hδ6 qδ6
Uniform 7-honeycomb {3[7]} δ7 hδ7 qδ7 222
Uniform 8-honeycomb {3[8]} δ8 hδ8 qδ8 133 • 331
Uniform 9-honeycomb {3[9]} δ9 hδ9 qδ9 152 • 251 • 521
Uniform n-honeycomb {3[n]} δn hδn qδn 1k2 • 2k1 • k21
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