SINAL = (trocaamar -> amarelo -> trocaverm -> verm -> trocaamar -> amarelo -> trocaverde -> verde -> SINAL).

||SIST = (s[1]:SINAL || s[2]:SINAL)
	      /{trocaamar/s[1..2].trocaamar,
	        amarelo/s[1..2].amarelo,
	        troca1/s[1..2].trocaverm,
	        troca2/s[1..2].trocaverde,
	        s[1].verde/s[1].verm,
	        s[1].verm/s[1].verde}.