# Square tiling

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{{Short description|Regular tiling of the Euclidean plane}}
{{Infobox face-uniform tiling
 | image = Tiling 4b.svg
 | name = Square tiling
 | type = [regular tiling](/source/regular_tiling)
 | tile = [square](/source/square)
 | vertex_config = 4.4.4.4
 | schläfli = <math> \{4,4\} </math>
 | symmetry = p4m
 | properties = [vertex-transitive](/source/vertex-transitive), [edge-transitive](/source/edge-transitive), [face-transitive](/source/face-transitive)
 | dual = [self-dual](/source/self-dual)
}}
In [geometry](/source/geometry), the '''square tiling''', '''square tessellation''' or '''square grid''' is a [regular tiling](/source/regular_tiling) of the [Euclidean plane](/source/Euclidean_plane) consisting of four [squares](/source/Square_(geometry)) around every [vertex](/source/Vertex_(geometry)). [John Horton Conway](/source/John_Horton_Conway) called it a '''quadrille'''.<ref name=conway>{{cite book
 | first1 = John H. | last1 = Conway | author1-link = John Horton Conway
 | first2 = Heidi | last2 = Burgiel
 | first3 = Chaim | last3 = Goodman-Strauss
 | title = The Symmetries of Things
 | title-link = The Symmetries of Things
 | year = 2008
 | publisher = AK Peters
 | isbn = 978-1-56881-220-5
 | page = [https://books.google.com/books?id=Drj1CwAAQBAJ&pg=PA288 288]
}}</ref>

== Structure and properties ==
{{multiple image
 | image1 = Lustenau, Rheinstraße 4, Küche, Fliesenboden.jpg
 | image2 = Chess.board.fabric.png
 | footer = Flooring and game board
 | total_width = 260
}}
The square tiling has a structure consisting of one type of congruent [prototile](/source/prototile), the [square](/source/square), sharing two vertices with other identical ones. This is an example of monohedral tiling.<ref name=adams>{{cite book
 | title = The Tiling Book: An Introduction to the Mathematical Theory of Tilings
 | first = Colin | last = Adams
 | publisher = American Mathematical Society
 | year = 2022
 | isbn = 9781470468972
 | pages = [https://books.google.com/books?id=LvGGEAAAQBAJ&pg=PA23 23]
}}</ref> Each vertex at the tiling is surrounded by four squares, which denotes in a [vertex configuration](/source/vertex_configuration) as <math> 4.4.4.4 </math> or <math> 4^4 </math>.{{sfnp|Grünbaum|Shephard|1987|p=[https://books.google.com/books?id=0x0vDAAAQBAJ&pg=PA59 59]}} The vertices of a square can be considered as the lattice, so the square tiling can be formed through the [square lattice](/source/square_lattice).<ref name=gs>{{cite book
 | last1 = Grünbaum | first1 = Branko | author-link1 = Branko Grunbaum
 | last2 = Shephard | first2 = G. C.
 | year = 1987
 | title = Tilings and Patterns
 | title-link = Tilings and patterns
 | publisher = W. H. Freeman
 | page = [https://books.google.com/books?id=0x0vDAAAQBAJ&pg=PA21 21], [https://books.google.com/books?id=0x0vDAAAQBAJ&pg=PA29 29]
}}</ref> This tiling is commonly familiar with the flooring and game boards.<ref name=sadun>{{cite book
 | first = Sadun | last = Lorenzo
 | title = Topology of Tiling Spaces
 | url = https://books.google.com/books?id=dL8FCAAAQBAJ&pg=PA1
 | page = 1
 | publisher = American Mathematical Society
 | year = 2008
| isbn = 978-0-8218-4727-5
 }}</ref> It is [self-dual](/source/self-dual), meaning the center of each square connects to another of the adjacent tile, forming square tiling itself.<ref name=ns>{{cite journal
 | last1 = Nelson | first1 = Roice
 | last2 = Segerman | first2 = Henry
 | title = Visualizing hyperbolic honeycombs
 | journal = Journal of Mathematics and the Arts
 | year = 2017
 | volume = 11 | issue = 1 | pages = 4–39
 | doi = 10.1080/17513472.2016.1263789
 | arxiv = 1511.02851
}}</ref>

The square tiling [acts transitively](/source/Group_action_(mathematics)) on the ''flags'' of the tiling. In this case, the [flag](/source/Flag_(geometry)) consists of a mutually incident vertex, edge, and tile of the tiling. Simply put, every pair of flags has a symmetry operation mapping the first flag to the second: they are [vertex-transitive](/source/vertex-transitive) (mapping the vertex of a tile to another), [edge-transitive](/source/edge-transitive) (mapping the edge to another), and [face-transitive](/source/face-transitive) (mapping square tile to another). By meeting these three properties, the square tiling is categorized as one of three [regular tiling](/source/regular_tiling)s; the remaining being [triangular tiling](/source/triangular_tiling) and [hexagonal tiling](/source/hexagonal_tiling) with its prototiles are [equilateral triangle](/source/equilateral_triangle)s and [regular hexagon](/source/regular_hexagon)s, respectively.{{sfnp|Grünbaum|Shephard|1987|p=[https://books.google.com/books?id=0x0vDAAAQBAJ&pg=PA35 35]}} The [symmetry group](/source/symmetry_group) of a square tiling is p4m: there is an [order-4 dihedral group](/source/Dihedral_group_of_order_4) of a tile and an order-2 [dihedral group](/source/dihedral_group) around the vertex surrounded by four squares lying on the line of reflection.{{sfnp|Grünbaum|Shephard|1987|p=[https://books.google.com/books?id=0x0vDAAAQBAJ&pg=PA42 42]|loc=see p. [https://books.google.com/books?id=0x0vDAAAQBAJ&pg=PA38 38] for detail of symbols}}

The square tiling is alternatively formed by the [assemblage of infinitely many circles](/source/Circle_packing) arranged vertically and horizontally, wherein their equal diameter at the center of every point contact with four other circles.<ref name=williams>{{cite book
 | last = Williams | first = Robert
 | year = 1979
 | title = The Geometrical Foundation of Natural Structure: A Source Book of Design
 | publisher = Dover Publications
 | isbn = 0-486-23729-X
 | page = 36
 | url = https://archive.org/details/geometricalfound00will/page/36/mode/1up?view=theater
}}</ref> Its densest packing is <math display="inline"> \frac{\pi}{4} \approx 0.785 </math>.<ref name=okeefe>{{cite journal
 | title = Plane nets in crystal chemistry
 | first1 = M. | last1 = O'Keeffe
 | first2 = B. G. | last2 = Hyde
 | journal = Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
 | volume = 295 | issue = 1417 | year = 1980
 | pages = 553–618
 | jstor = 36648
 | doi = 10.1098/rsta.1980.0150
 | bibcode = 1980RSPTA.295..553O
 | s2cid = 121456259
}}</ref>

== Topologically equivalent tilings ==
Isohedral tilings have identical faces ([face-transitivity](/source/Face-transitive)) and [vertex-transitivity](/source/vertex-transitive). There are eighteen variations, with six identified as triangles that do not connect edge-to-edge, or as quadrilateral with two collinear edges. Symmetry given assumes all faces are the same color.{{sfnp|Grünbaum|Shephard|1987|p=[https://books.google.com/books?id=0x0vDAAAQBAJ&pg=PA473 473&ndash;481]}}

{{multiple image
| perrow            = 6
| align             = center
| image1            = Isohedral tiling p4-49.svg
| image2            = Lattice of rectangles.svg
| image3            = Lattice of rhomboids.svg
| image4            = Isohedral tiling p4-51c.svg
| image5            = Lattice of rhombuses.svg
| image6            = Isohedral tiling p4-51c.svg
| image7            = Isohedral tiling p4-52b.svg
| image8            = Isohedral tiling p4-52.svg
| image9            = Isohedral tiling p4-46.svg
| image10           = Isohedral tiling p4-53.svg
| image11           = Isohedral tiling p4-47.svg
| image12           = Isohedral tiling p4-43.svg
| image13           = Isohedral tiling p3-7.svg
| image14           = Isohedral tiling p3-4.svg
| image15           = Isohedral tiling p3-5.svg
| image16           = Isohedral tiling p3-3.svg
| image17           = Isohedral tiling p3-6.svg
| image18           = Isohedral tiling p3-2.svg
| total_width       = 700
| footer            = Twelve isohedral quadrilateral tilings, and six triangular tilings that do not tile edge-to-edge
}}

== Related regular complex apeirogons ==
There are 3 [regular complex apeirogon](/source/regular_complex_apeirogon)s, sharing the vertices of the square tiling. Regular complex apeirogons have vertices and edges, where edges can contain 2 or more vertices. Regular apeirogons p{q}r are constrained by: 1/''p'' + 2/''q'' + 1/''r'' = 1. Edges have ''p'' vertices, and vertex figures are ''r''-gonal.<ref>Coxeter, Regular Complex Polytopes, pp. 111-112, p. 136.</ref>
{| class=wikitable
!Self-dual||colspan=2|Duals
|-
|160px
|160px
|160px
|-
!4{4}4 or {{CDD|4node_1|4|4node}}
!2{8}4 or {{CDD|node_1|8|4node}}
!4{8}2 or {{CDD|4node_1|8|node}}
|}

==See also==
{{Commons category|Order-4 square tiling}}
* [Tiling with rectangles](/source/Tiling_with_rectangles)
* [Fenestrane](/source/Fenestrane)
* [Langton's ant](/source/Langton's_ant)
* [OpenStructures](/source/OpenStructures), design pattern consisting of four squares around every vertex
* [Polyomino](/source/Polyomino)

== References ==
{{reflist}}
* [Coxeter, H.S.M.](/source/Coxeter) ''[Regular Polytopes](/source/Regular_Polytopes_(book))'', (3rd edition, 1973), Dover edition, {{isbn|0-486-61480-8}} p.&nbsp;296, Table II: Regular honeycombs

== External links ==
* {{MathWorld | urlname=SquareGrid | title=Square Grid}}
* {{MathWorld | urlname=RegularTessellation | title=Regular tessellation}}
* {{MathWorld | urlname=UniformTessellation | title=Uniform tessellation}}

{{Honeycombs}}
{{Tessellation}}

Category:Euclidean tilings
Category:Isohedral tilings
Category:Isogonal tilings
Category:Polyhedra
Category:Regular tilings
Category:Self-dual tilings
Category:Square tilings
Category:Regular tessellations

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Adapted from the Wikipedia article [Square tiling](https://en.wikipedia.org/wiki/Square_tiling) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Square_tiling?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.
