Spontaneous Emergence of Spatio-Temporal Order in Class 4 Automata
  We report surprisingly regular behaviors observed for a class 4 cellular automaton, the totalistic rule 20: starting from disordered initial configurations the automaton produces patterns which are periodic not only in time but also in space. This is the first evidence that different types of spatio-temporal order can emerge under specific conditions out of disorder in the same discrete rule based algorithm. 
Jason A.C. Gallas and Hans J. Herrmann