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.]
© 2002 by Stephen Wolfram,