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We prove that the following problem is co-RE-complete and thus undecidable: given three simple polygons, is there a tiling of the plane where every tile is an isometry of one of the three polygons (either allowing or forbidding…

Computational Geometry · Computer Science 2024-09-19 Erik D. Demaine , Stefan Langerman

The number of ways to tile an $n$-board (an $n\times1$ rectangular board) with $(\frac12,\frac12;1)$-, $(\frac12,\frac12;2)$-, and $(\frac12,\frac12;3)$-combs is $T_{n+2}^2$ where $T_n$ is the $n$th tribonacci number. A…

Combinatorics · Mathematics 2024-09-04 Michael A. Allen , Kenneth Edwards

R. Nandakumar asked whether there is a tiling of the plane by pairwise incongruent triangles of equal area and equal perimeter. Recently a negative answer was given by Kupavskii, Pach and Tardos. Still one may ask for weaker versions of the…

Combinatorics · Mathematics 2020-04-02 Dirk Frettlöh , Christian Richter

A tiling of the unit square is an MTP tiling if the smallest tile can tile all the other tiles. We look at the function $f(n)=\max \sum s_i$, where $s_i$ is the side length of the $i$th tile and the sum is taken over all MTP tilings with…

Metric Geometry · Mathematics 2020-05-05 Iwan Praton

This paper characterizes when an $m \times n$ rectangle, where $m$ and $n$ are integers, can be tiled (exactly packed) by squares where each has an integer side length of at least 2. In particular, we prove that tiling is always possible…

Computational Geometry · Computer Science 2023-08-30 MIT CompGeom Group , Zachary Abel , Hugo A. Akitaya , Erik D. Demaine , Adam C. Hesterberg , Jayson Lynch

We show how to determine if a given simple rectilinear polygon can be tiled with rectangles, each having an integer side.

Combinatorics · Mathematics 2009-09-25 Richard Kenyon

In this paper we give a classification of tilings of the sphere by congruent quadrilaterals with exactly two equal edges. The tilings are the earth map tilings, $(p,q)$-earth map tilings and their flip modifications, and quadrilateral…

Combinatorics · Mathematics 2021-09-06 Ho Man Cheung , Hoi Ping Luk

A method is described for constructing, with computer assistance, planar substitution tilings that have n-fold rotational symmetry. This method uses as prototiles the set of rhombs with angles that are integer multiples of pi/n, and…

Metric Geometry · Mathematics 2015-10-06 Gregory R. Maloney

We know that tilesets that can tile the plane always admit a quasi-periodic tiling [4, 8], yet they hold many uncomputable properties [3, 11, 21, 25]. The quasi-periodicity function is one way to measure the regularity of a quasi-periodic…

Cellular Automata and Lattice Gases · Physics 2010-12-07 Alexis Ballier , Emmanuel Jeandel

Let T be a tile in the Cartesian plane made up of finitely many rectangles whose corners have rational coordinates and whose sides are parallel to the coordinate axes. This paper gives necessary and sufficient conditions for a square to be…

Combinatorics · Mathematics 2007-05-23 Kevin Keating

In this paper, we show that an equilateral triangle cannot be dissected into finitely many smaller equilateral triangles, no two of which share two vertices. We do this without the use of Electrical Networks.

History and Overview · Mathematics 2014-12-18 Timothy Chu

A plane tiling consisting of congruent copies of a shape is isohedral provided that for any pair of copies, there exists a symmetry of the tiling mapping one copy to the other. We give a $O(n\log^2{n})$-time algorithm for deciding if a…

Computational Geometry · Computer Science 2016-03-10 Stefan Langerman , Andrew Winslow

Since the thesis of K. Reinhardt in 1918, it is well known that there are exactly three types of convex hexagons that can tile the plane. However, the proof of the fact is far from being complete. We prove this fact, under an assumption…

Combinatorics · Mathematics 2026-04-29 Ze Zhu , Erxiao Wang , Min Yan

This paper focuses on the undecidability of translational tiling of $n$-dimensional space $\mathbb{Z}^n$ with a set of $k$ tiles. It is known that tiling $\mathbb{Z}^2$ with translated copies with a set of $8$ tiles is undecidable.…

Combinatorics · Mathematics 2025-06-24 Chao Yang , Zhujun Zhang

In [BNRR], it was shown that tiling of general regions with two rectangles is NP-complete, except for a few trivial special cases. In a different direction, R\'emila showed that for simply connected regions by two rectangles, the…

Combinatorics · Mathematics 2013-05-14 Igor Pak , Jed Yang

Let n integer greater or equal to 4 and even and let T_n be the set of ribbon L-shaped n-ominoes. We study tiling problems for regions in a square lattice by T_n. Our main result shows a remarkable rigidity property: a tiling of the first…

Combinatorics · Mathematics 2014-06-04 Viorel Nitica

We show it is possible to tile three-dimensional space using only tetrahedra with acute dihedral angles. We present several constructions to achieve this, including one in which all dihedral angles are less than $77.08^\circ$, and another…

Computational Geometry · Computer Science 2007-05-23 David Eppstein , John M. Sullivan , Alper Ungor

Aperiodic tilings are non-periodic tilings defined by local rules. They are widely used to model quasicrystals, and a central question is to understand which of the non-periodic tilings are actually aperiodic. Among tilings, those by rhombi…

Dynamical Systems · Mathematics 2015-09-24 Nicolas Bédaride , Thomas Fernique

A triangle $T'$ is $\varepsilon$-similar to another triangle $T$ if their angles pairwise differ by at most $\varepsilon$. Given a triangle $T$, $\varepsilon>0$ and $n\in\mathbb{N}$, B\'ar\'any and F\"uredi asked to determine the maximum…

Combinatorics · Mathematics 2022-05-03 József Balogh , Felix Christian Clemen , Bernard Lidický

We apply Diophantine analysis to classify edge-to-edge tilings of the sphere by congruent almost equilateral quadrilaterals (i.e., edge combination a3b). Parallel to a complete classification by Cheung, Luk and Yan, the method implemented…

Combinatorics · Mathematics 2022-08-05 Ho Man Cheung , Hoi Ping Luk