Wang tile

They used an exhaustive computer search to prove that 10 tiles or 3 colors are insufficient to force aperiodicity.

[8] This set, shown above in the title image, can be examined more closely at File: Wang 11 tiles.svg.

Culik and Kari have demonstrated aperiodic sets of Wang cubes.

[10] Mittal et al. have shown that these tiles can also be composed of peptide nucleic acid (PNA), a stable artificial mimic of DNA.

[11] Wang tiles have been used for procedural synthesis of textures, heightfields, and other large and nonrepeating bi-dimensional data sets; a small set of precomputed or hand-made source tiles can be assembled very cheaply without too obvious repetitions and periodicity.

[12][13][14][15][16] Wang tiles have also been used in cellular automata theory decidability proofs.

[17] The short story "Wang's Carpets", later expanded to the novel Diaspora, by Greg Egan, postulates a universe, complete with resident organisms and intelligent beings, embodied as Wang tiles implemented by patterns of complex molecules.