Loop of length 10 starting with a string of length 4
found after enumerating 480 derivations:

.ca.aa
	rule ca -> aabacbc at position 0
.aabacbc.aa
	rule ca -> aabacbc at position 6
.aabacbaabacbc.a
	rule a ->  at position 6
.aabacbabacbc.a
	rule a ->  at position 6
.aabacbbacbc.a
	rule bb ->  at position 5
.aabacacbc.a
	rule ca -> aabacbc at position 8
.aabacacbaabacbc.
	rule a ->  at position 8
.aabacacbabacbc.
	rule a ->  at position 8
.aabacacbbacbc.
	rule bb ->  at position 7
.aabacacacbc.
	rule ca -> aabacbc at position 6
.aabacaaabacbccbc.