Loop of length 4 starting with a string of length 13
found after enumerating 6 derivations:

.abcbc.bcbcbcbc
	rule abcbc -> cbcbcbaba at position 0
.cbcbcbaba.bcbcbcbc
	rule abcbc -> cbcbcbaba at position 8
.cbcbcbabcbcbcbaba.bcbc
	rule abcbc -> cbcbcbaba at position 16
.cbcbcbabcbcbcbabcbcbcbaba.
	rule abcbc -> cbcbcbaba at position 14
.cbcbcbabcbcbcbcbcbcbababcbaba.