Loop of length 7 starting with a string of length 4
found after enumerating 97 derivations:

.ca.aa
	rule ca -> aacbac at position 0
.aacbac.aa
	rule a ->  at position 4
.aacbc.aa
	rule ca -> aacbac at position 4
.aacbaacbac.a
	rule a ->  at position 4
.aacbacbac.a
	rule a ->  at position 4
.aacbcbac.a
	rule bcb ->  at position 3
.aacac.a
	rule ca -> aacbac at position 4
.aacaaacbac.