Triangular tiling

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Triangular tiling
Triangular tiling
Type Regular tiling
Vertex configuration 3.3.3.3.3.3 (or 36)
Triangular tiling vertfig.png
Schläfli symbol(s) {3,6}
{3[3]}
Wythoff symbol(s) 6 | 3 2
3 | 3 3
| 3 3 3
Coxeter diagram(s) CDel node.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node 1.png
CDel node.pngCDel 6.pngCDel node h.pngCDel 3.pngCDel node h.png
CDel node 1.pngCDel split1.pngCDel branch.png = CDel node h1.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node.png
CDel node h.pngCDel split1.pngCDel branch hh.png
Symmetry p6m, [6,3], (*632)
Rotation symmetry p6, [6,3]+, (632)
p3, [3[3]]+, (333)
Dual Hexagonal tiling
Properties Vertex-transitive, edge-transitive, face-transitive

In geometry, the triangular tiling or triangular tessellation is one of the three regular tilings of the Euclidean plane. Because the internal angle of the equilateral triangle is 60 degrees, six triangles at a point occupy a full 360 degrees. The triangular tiling has Schläfli symbol of {3,6}.

Conway calls it a deltille, named from the triangular shape of the Greek letter delta (Δ). The triangular tiling can also be called a kishextille by a kis operation that adds a center point and triangles to replace the faces of a hextille.

It is one of three regular tilings of the plane. The other two are the square tiling and the hexagonal tiling.

Uniform colorings[edit]

There are 9 distinct uniform colorings of a triangular tiling. (Naming the colors by indices on the 6 triangles around a vertex: 111111, 111112, 111212, 111213, 111222, 112122, 121212, 121213, 121314) Three of them can be derived from others by repeating colors: 111212 and 111112 from 121213 by combining 1 and 3, while 111213 is reduced from 121314.[1]

There is one Archimedean coloring 111112, (marked with a *) which is not 1-uniform, containing alternate rows of triangles where every third is colored. The example given is 2-uniform, but there are infinitely many such Archimedean colorings that can be created by arbitrary horizontal shifts of the rows.

111111 121212 111222 112122 111112(*)
Uniform tiling 63-t2.png Uniform tiling 333-t1.png Uniform triangular tiling 111222.png Uniform triangular tiling 112122.png 2-uniform triangular tiling 111112.png
p6m (*632) p3m1 (*333) cmm (2*22) p2 (2222) p2 (2222)
121213 111212 111112 121314 111213
Uniform triangular tiling 121213.png Uniform triangular tiling 111212.png Uniform triangular tiling 111112.png Uniform triangular tiling 121314.png Uniform triangular tiling 111213.png
p3m1 (*333) p31m (3*3) p3 (333)

A2 lattice and circle packings[edit]

The A*
2
lattice as three triangular tilings: CDel node 1.pngCDel split1.pngCDel branch.png + CDel node.pngCDel split1.pngCDel branch 10lu.png + CDel node.pngCDel split1.pngCDel branch 01ld.png

The vertex arrangement of the triangular tiling is called an A2 lattice.[2] It is the 2-dimensional case of a simplectic honeycomb.

The A*
2
lattice (also called A3
2
) can be constructed by the union of all three A2 lattices, and equivalent to the A2 lattice.

CDel node 1.pngCDel split1.pngCDel branch.png + CDel node.pngCDel split1.pngCDel branch 10lu.png + CDel node.pngCDel split1.pngCDel branch 01ld.png = dual of CDel node 1.pngCDel split1.pngCDel branch 11.png = CDel node 1.pngCDel split1.pngCDel branch.png

The vertices of the triangular tiling are the centers of the densest possible circle packing.[3] Every circle is in contact with 6 other circles in the packing (kissing number). The packing density is \frac{\pi}{\sqrt{12}} or 90.69%. Since the union of 3 A2 lattices is also an A2 lattice, the circle packing can be given with 3 colors of circles.

The voronoi cell of a triangular tiling is a hexagon, and so the voronoi tessellation, the hexagonal tiling has a direct correspondence to the circle packings.

A2 lattice circle packing A*
2
lattice circle packing
Triangular tiling circle packing.png Triangular tiling circle packing3.png

Geometric variations[edit]

Triangular tilings can be made with the equivalent {3,6} topology as the regular tiling (6 triangles around every vertex). With identical faces (face-transitivity) and vertex-transitivity, there are 5 variations. Symmetry given assumes all faces are the same color.[4]

Related polyhedra and tilings[edit]

The planar tilings are related to polyhedra. Putting fewer triangles on a vertex leaves a gap and allows it to be folded into a pyramid. These can be expanded to Platonic solids: five, four and three triangles on a vertex define an icosahedron, octahedron, and tetrahedron respectively.

This tiling is topologically related as a part of sequence of regular polyhedra with Schläfli symbols {3,n}, continuing into the hyperbolic plane.

*n32 symmetry mutation of regular tilings: 3n or {3,n}
Spherical Euclid. Compact hyper. Paraco. Noncompact hyperbolic
Trigonal dihedron.png Uniform tiling 332-t2.png Uniform tiling 432-t2.png Uniform tiling 532-t2.png Uniform polyhedron-63-t2.png H2 tiling 237-4.png H2 tiling 238-4.png H2 tiling 23i-4.png H2 tiling 23j12-4.png H2 tiling 23j9-4.png H2 tiling 23j6-4.png H2 tiling 23j3-4.png
3.3 33 34 35 36 37 38 3 312i 39i 36i 33i

It is also topologically related as a part of sequence of Catalan solids with face configuration Vn.6.6, and also continuing into the hyperbolic plane.

Triakistetrahedron.jpg
V3.6.6
Tetrakishexahedron.jpg
V4.6.6
Pentakisdodecahedron.jpg
V5.6.6
Uniform polyhedron-63-t2.png
V6.6.6
Order3 heptakis heptagonal til.png
V7.6.6

Wythoff constructions from hexagonal and triangular tilings[edit]

Like the uniform polyhedra there are eight uniform tilings that can be based from the regular hexagonal tiling (or the dual triangular tiling).

Drawing the tiles colored as red on the original faces, yellow at the original vertices, and blue along the original edges, there are 8 forms, 7 which are topologically distinct. (The truncated triangular tiling is topologically identical to the hexagonal tiling.)

Uniform hexagonal/triangular tilings
Fundamental
domains
Symmetry: [6,3], (*632) [6,3]+, (632)
{6,3} t{6,3} r{6,3} t{3,6} {3,6} rr{6,3} tr{6,3} sr{6,3}
CDel node 1.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node.png CDel node 1.pngCDel 6.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 6.pngCDel node 1.pngCDel 3.pngCDel node.png CDel node.pngCDel 6.pngCDel node 1.pngCDel 3.pngCDel node 1.png CDel node.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node 1.png CDel node 1.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node 1.png CDel node 1.pngCDel 6.pngCDel node 1.pngCDel 3.pngCDel node 1.png CDel node h.pngCDel 6.pngCDel node h.pngCDel 3.pngCDel node h.png
Tiling Dual Semiregular V4-6-12 Bisected Hexagonal.svg Uniform tiling 63-t0.png Uniform tiling 63-t01.png Uniform tiling 63-t1.png Uniform tiling 63-t12.png Uniform tiling 63-t2.png Uniform tiling 63-t02.png Uniform tiling 63-t012.png Uniform tiling 63-snub.png
Config. 63 3.12.12 (6.3)2 6.6.6 36 3.4.6.4 4.6.12 3.3.3.3.6
Wythoff 3 | 3 3 3 3 | 3 3 | 3 3 3 3 | 3 3 | 3 3 3 3 | 3 3 3 3 | | 3 3 3
Coxeter CDel node 1.pngCDel split1.pngCDel branch.png CDel node 1.pngCDel split1.pngCDel branch 10l.png CDel node.pngCDel split1.pngCDel branch 10l.png CDel node.pngCDel split1.pngCDel branch 11.png CDel node.pngCDel split1.pngCDel branch 01l.png CDel node 1.pngCDel split1.pngCDel branch 01l.png CDel node 1.pngCDel split1.pngCDel branch 11.png CDel node h.pngCDel split1.pngCDel branch hh.png
Image
Vertex figure
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

Other triangular tilings[edit]

There are also three Laves tilings made of single type of triangles:

1-uniform 3 dual.svg
Kisrhombille
30°-60°-90° right triangles
1-uniform 2 dual.svg
Kisquadrille
45°-45°-90° right triangles
1-uniform 4 dual.svg
Kisdeltile
30°-30°-120° isosceles triangles

See also[edit]

References[edit]

  1. ^ Tilings and Patterns, p.102-107
  2. ^ http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/A2.html
  3. ^ Order in Space: A design source book, Keith Critchlow, p.74-75, pattern 1
  4. ^ Tilings and Patterns, from list of 107 isohedral tilings, p.473-481

External links[edit]