Domino Substitution Tilings
Domino Substitution Tilings
Tiling substitution rules specify how to fill and then subdivide a tile into copies of itself. Iterating these rules, we can form larger and larger "supertiles" and ultimately define substitution tilings, which are divisions of the plane into infinite hierarchies of supertiles. The configuration shown here, of four dominoes (2×1 rectangles, also known as dimers) forming a larger one, does not give a well-defined substitution rule: in order to iterate such a rule, we must further specify how the smaller dominoes are oriented in the large one, possibly with several choices.