Loop of length 12 starting with a string of length 7
found after enumerating 20005 derivations:

.a.abbbbb
	rule a -> bbc at position 0
.bbc.abbbbb
	rule cab -> aca at position 2
.bbaca.bbbb
	rule cab -> aca at position 3
.bbaaca.bbb
	rule cab -> aca at position 4
.bbaaaca.bb
	rule a -> bbc at position 4
.bbaabbcca.bb
	rule cab -> aca at position 7
.bbaabbcaca.b
	rule cab -> aca at position 8
.bbaabbcaaca.
	rule a -> bbc at position 8
.bbaabbcabbcca.
	rule cab -> aca at position 6
.bbaabbacabcca.
	rule a -> b at position 6
.bbaabbbcabcca.
	rule cab -> aca at position 7
.bbaabbbacacca.
	rule a -> bbc at position 7
.bbaabbbbbccacca.