15 steps wm4486wm4486 signature 22→4222→12 rule {{{1, 1}, {2, 3}} -> {{2, 2}, {2, 1}, {2, 3}, {4, 2}}, {{1, 2}, {1, 2}} -> {{3, 2}}} {{{1, 1}, {2, 3}} -> {{2, 2}, {2, 1}, {2, 3}, {4, 2}}, {{1, 2}, {1, 2}} -> {{3, 2}}}