Loop of length 10 starting with a string of length 10
found after enumerating 120 derivations:

.ab.bbbbbbbb
	rule ab -> bc at position 0
.bc.bbbbbbbb
	rule cbb -> bbbaa at position 1
.bbbbaa.bbbbbb
	rule ab -> bc at position 5
.bbbbabc.bbbbb
	rule cbb -> bbbaa at position 6
.bbbbabbbbaa.bbb
	rule ab -> bc at position 10
.bbbbabbbbabc.bb
	rule ab -> bc at position 9
.bbbbabbbbbcc.bb
	rule cbb -> bbbaa at position 11
.bbbbabbbbbcbbbaa.
	rule cbb -> bbbaa at position 10
.bbbbabbbbbbbbaabaa.
	rule ab -> bc at position 14
.bbbbabbbbbbbbabcaa.
	rule ab -> bc at position 13
.bbbbabbbbbbbbbccaa.