Loop of length 7 starting with a string of length 4
found after enumerating 217 derivations:

.ab.cb
	rule ab -> baacb at position 0
.baacb.cb
	rule b -> a at position 4
.baaca.cb
	rule a ->  at position 4
.baac.cb
	rule cc ->  at position 3
.baa.b
	rule ab -> baacb at position 2
.babaacb.
	rule a ->  at position 3
.babacb.
	rule a ->  at position 3
.babcb.