An one-dimensional substitution rule that uses an infinite number of proto tiles and yields a transcendental inflation multiplier. The inflation factor is approximately $2.7899$. The substitution rules are given by: $T_{0}\rightarrow T_{0},T_{1}$ $T_{1}\rightarrow 3T_{0},T_{2}$ $T_{2}\rightarrow 2T_{0},T_{1},T_{3}$ $T_{3}\rightarrow T_{0},T_{2},T_{4}$ $T_{4}\rightarrow 2T_{0},T_{3},T_{5}$ $T_{5}\rightarrow T_{0},T_{4},T_{6}$ $T_{6}\rightarrow T_{0},T_{5},T_{7}$ $T_{k}\rightarrow (1+f\left(k\right))T_{0},T_{k-1},T_{k+1}$ with $f\left(k\right)$ as the Thue-Morse sequence. The corresponding substitution matrix can be written as: $1 3 2 1 2 1 1 2 2 ...$

One Dimensional Self Similar Substitution

A substitution rule that gives rise to an aperiodic tiling with dense tile orientations and 5-fold rotational symmetry. The inflation factor is $\sqrt{6+\sqrt{5}}$. The tiling has finite local complexity with respect to rigid motions.

Finite Local Complexity Polytopal Tiles Self Similar Substitution

A decorated version of the Hofstetter 4fold tilings. This version can be generated by a proper substitution rule. It was shown in [FH15] that this version is aperiodic, as well as limitperiodic. For more details see Hofstetters 4-fold.

P Adic Windowed Tiling Polytopal Tiles

One example in a series of substitutions with inflation factor $\sqrt{s}$, where $s^m-s^k-1=0$. The parameters m and k are arbitrary integers with m>k, m>2, k>0. It seems that all these tilings show statistical circular symmetry. Click on ‘Infinite rotations’ above in order to see more examples of statistical circular symmetric tilings. The substitution is a slight variation of the substitution underlying Chaim’s cubic PV. The trick is that the free parameter in Chaim’s rule is choosen such that the prototiles become equilateral triangles.

Infinite Rotations Finite Local Complexity Polytopal Tiles Self Similar Substitution

This substitution arises from a reptile with infinitely many straight edges, cf. [GS87]. It answers the question ‘Are there selfsimilar substitution tilings where the prototiles have infinitely many straight edges?’ positively. The colours of the tiles indicate their chirality. The substitution rule is shown for the right handed tile only, the substitution of the left-handed tile is the reflected image. One can easily define a substitution using only the right handed tile, but this generates periodic tilings only.

Finite Rotations Rep Tiles

This one is mld to the semi-detached house tiling. A view at the latter (hopefully) explains the name. This version was realized in order to prove (or disprove) that the semi detached house tiling is a cut and project tiling with p-adic internal space. This is not the case, as was shown in [FS].

Finite Rotations Polytopal Tiles Parallelogram Tiles Rhomb Tiles Self Similar Substitution

A substitution rule for a tiling with prototiles based on 12-fold dihedral symmetry. However, the tilings show only 4-fold dihedral symmetry. In contrast to the usual suspects related to 12-fold symmetry, like the shield tilings or the Socolar tilings, the inflation factor of this one is not an algebraic unit. It is still a PV number, which makes this tiling a candidate for a model set with mixed p-adic and Euclidean window.

Finite Rotations Polytopal Tiles

A substitution tiling with statistical eight-fold symmetry. This example answers a question of L. Danzer, whether there is a substitution tiling with substitution matrix with entries 1,2,2,5.

In order to generalize Danzer’s 7-fold tiling to n-fold symmetry, where n>5 is odd, L. Danzer and D. Frettlöh introduced trapezoidal tiles, each one the union of two triangles with edge lengths of the form $\sin(k \frac{\pi}{n})$. It needs some further effort, including the introduction of three additional prototiles (two pentagons, one non-trapezoidal quadrangle), but one obtains an infinite series of substitution rules based on n-fold symmetry (n odd). Unfortunately, none of these tilings show perfect n-fold symmetry, as Danzer’s 7-fold does, thus loosing aesthetic appeal.

In order to generalize Danzer’s 7-fold tiling to n-fold symmetry, where n>5 is odd, L. Danzer and D. Frettlöh introduced trapezoidal tiles, each one the union of two triangles with edge lengths of the form $\sin(k \frac{\pi}{n})$. It needs some further effort, including the introduction of three additional prototiles (two pentagons, one non-trapezoidal quadrangle), but one obtains an infinite series of substitution rules based on n-fold symmetry (n odd). Unfortunately, none of these tilings show perfect n-fold symmetry, as Danzer’s 7-fold does, thus loosing aesthetic appeal.

In order to generalize Danzer’s 7-fold tiling to n-fold symmetry, where n>5 is odd, L. Danzer and D. Frettlöh introduced trapezoidal tiles, each one the union of two triangles with edge lengths of the form $\sin(k \frac{\pi}{n})$. It needs some further effort, including the introduction of three additional prototiles (two pentagons, one non-trapezoidal quadrangle), but one obtains an infinite series of substitution rules based on n-fold symmetry (n odd). Unfortunately, none of these tilings show perfect n-fold symmetry, as Danzer’s 7-fold does, thus loosing aesthetic appeal.

Using the prototiles of the golden triangle tiling, this substitution yields tilings where the tiles occur in infinitely many orientations. The inflation factor is $\tau + 1 = 2.618033988 \ldots $, the square of the golden mean. This is a PV number of algebraic degree 2. The expansion contains no rotational part. Nevertheless, the first substitution of the larger tile shows two small tiles, rotated against each other by an angle a incommensurate to pi (i.e., $\frac{a}{\pi}$ is irrational).

Finite Local Complexity Polytopal Tiles Self Similar Substitution

This is a variation of the pinwheel substitution. The kite-domino tilings are mld to the pinwheel tilings. The two prototiles are made of two pinwheel triangles, glued together at their long edge. There are two ways to do so, one gives a kite (a quadrilateral with edge lengths 1,1,2,2) and a domino (a rectangle with edge lengths 1,2,1,2). Then the substitution rule is obtained by considering two steps of the pinwheel substitution as one step.

With Decoration Finite Local Complexity Polytopal Tiles Self Similar Substitution Mld Class Pinwheel

A simple substitution rule with inflation factor 2, using two prototiles only. A glimpse on the image hopefully explains the name. The translation module is a square lattice, which is a hint that the semi-detached house tilings may be a model set with p-adic internal space. This question (model set or not) was raised in [Fre02] and was answered in [FS] .

Finite Rotations Polytopal Tiles Self Similar Substitution

A simple example of an infinite series of substitutions with tilings of statistical circular symmetry. It is shown in [Frettloeh:STWCS not found], that all tilings in this series posses statistical circular symmetry. The substitution factors are $s2m$, where s is the largest root of $xm-xk-1$. Each pair of integers $(m,k)$, where $m>k, m>2, k>0$, encodes a such a Pythia substitution. The case $m=4, k=2$ yields the golden pinwheel substitution.

Finite Local Complexity Polytopal Tiles Self Similar Substitution