A two-dimensional cellular automaton that yields a pattern with a rough surface. The rule used here includes diagonal neighbors, and so involves a total of 8 neighbors for each cell, as indicated in the icon on the bottom left. The rule specifies that the center cell should become black if either 3 or 5 of its 8 neighbors were black on the step before, and should otherwise stay the same color as it was before. The initial condition in the case shown consists of a row of 7 black cells. In an extension to 8 neighbors of the scheme used in the pictures a few pages back, the rule has code number 175850.

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