Sequential substitution systems that emulate cellular automata with rules 90 and 30. The pictures at the top above are obtained by keeping only the steps indicated by arrows on the left. The sequential substitution systems involve elements with 3 possible colors.

Tag systems that emulate the rule 90 and rule 30 cellular automata. The pictures at the top above are obtained by keeping only the steps indicated by arrows on the left. Both tag systems involve 6 colors.