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Wolfram's Rule 22 (or W22) is the 2-state 1-D cellular automaton in which a cell is ON in the next generation if and only if exactly one of its three neighbours is ON in the current generation (a cell being counted as a neighbour of itself). This is the behaviour of Life on a cylinder of width 1.
Unlike Rule 90, Rule 22 is capable of explosive growth given a sufficiently chaotic input.