A New Kind of Science: NKS 2004 Conference & Minicourse: Gallery

Stephen Wolfram
Examples of nested patterns created by following the two-dimensional substitution rules shown. Except for the last examples on each row, it is remarkably difficult to recognize the nested structure in these patterns by eye, even with quite careful scrutiny. The two-dimensional pointer-based encoding scheme from page 571 does however manage to recognize the structure in all cases.

[From A New Kind of Science, page 583.]