[Generalized substitution system] rule (b)

The maximum number of steps for which the rule can be applied occurs with initial conditions consisting of a white element followed by n black elements, and in this case the number of steps is 2^{n} + n.

[Generalized substitution system] rule (b)

The maximum number of steps for which the rule can be applied occurs with initial conditions consisting of a white element followed by n black elements, and in this case the number of steps is 2^{n} + n.

From Stephen Wolfram: *A New Kind of Science* [citation]