Loop of length 4 starting with a string of length 7
found after enumerating 6 derivations:

.abbcb.bb
	rule abbcb -> bbcbaabbc at position 0
.bbcbaabbc.bb
	rule abbcb -> bbcbaabbc at position 5
.bbcbabbcbaabbc.b
	rule abbcb -> bbcbaabbc at position 10
.bbcbabbcbabbcbaabbc.
	rule abbcb -> bbcbaabbc at position 9
.bbcbabbcbbbcbaabbcaabbc.