Loop of length 13 starting with a string of length 7
found after enumerating 12910 derivations:

.cb.bbbbb
	rule cb -> bbac at position 0
.bbac.bbbbb
	rule cb -> bbac at position 3
.bbabbac.bbbb
	rule b ->  at position 3
.bbabac.bbbb
	rule b ->  at position 3
.bbaac.bbbb
	rule cb -> bbac at position 4
.bbaabbac.bbb
	rule b ->  at position 4
.bbaabac.bbb
	rule b ->  at position 4
.bbaaac.bbb
	rule aaa -> c at position 2
.bbcc.bbb
	rule cb -> bbac at position 3
.bbcbbac.bb
	rule a ->  at position 5
.bbcbbc.bb
	rule cb -> bbac at position 5
.bbcbbbbac.b
	rule a ->  at position 7
.bbcbbbbc.b
	rule cb -> bbac at position 7
.bbcbbbbbbac.