Loop of length 19 starting with a string of length 6
found after enumerating 19237 derivations:

.aa.cccc
	rule aa -> cbb at position 0
.cbb.cccc
	rule bc -> cab at position 2
.cbcab.ccc
	rule bc -> cab at position 1
.ccabab.ccc
	rule b ->  at position 3
.ccaab.ccc
	rule aa -> cbb at position 2
.cccbbb.ccc
	rule bc -> cab at position 5
.cccbbcab.cc
	rule bc -> cab at position 4
.cccbcabab.cc
	rule bc -> cab at position 3
.ccccababab.cc
	rule b ->  at position 5
.ccccaabab.cc
	rule a ->  at position 7
.ccccaabb.cc
	rule bc -> cab at position 7
.ccccaabcab.c
	rule bc -> cab at position 6
.ccccaacabab.c
	rule b ->  at position 8
.ccccaacaab.c
	rule aa -> cbb at position 7
.ccccaaccbbb.c
	rule b ->  at position 8
.ccccaaccbb.c
	rule bc -> cab at position 9
.ccccaaccbcab.
	rule bc -> cab at position 8
.ccccaacccabab.
	rule b ->  at position 10
.ccccaacccaab.
	rule aa -> cbb at position 9
.ccccaaccccbbb.