Loop of length 16 starting with a string of length 17
found after enumerating 416 derivations:

.abbbb.bbbbbbbbbbbb
	rule abbbb -> bbbbaab at position 0
.bbbbaab.bbbbbbbbbbbb
	rule abbbb -> bbbbaab at position 5
.bbbbabbbbaab.bbbbbbbbb
	rule abbbb -> bbbbaab at position 10
.bbbbabbbbabbbbaab.bbbbbb
	rule abbbb -> bbbbaab at position 9
.bbbbabbbbbbbbaabaab.bbbbbb
	rule abbbb -> bbbbaab at position 17
.bbbbabbbbbbbbaababbbbaab.bbb
	rule abbbb -> bbbbaab at position 16
.bbbbabbbbbbbbaabbbbbaabaab.bbb
	rule abbbb -> bbbbaab at position 14
.bbbbabbbbbbbbabbbbaabbaabaab.bbb
	rule abbbb -> bbbbaab at position 13
.bbbbabbbbbbbbbbbbaabaabbaabaab.bbb
	rule abbbb -> bbbbaab at position 28
.bbbbabbbbbbbbbbbbaabaabbaababbbbaab.
	rule abbbb -> bbbbaab at position 27
.bbbbabbbbbbbbbbbbaabaabbaabbbbbaabaab.
	rule abbbb -> bbbbaab at position 25
.bbbbabbbbbbbbbbbbaabaabbabbbbaabbaabaab.
	rule abbbb -> bbbbaab at position 24
.bbbbabbbbbbbbbbbbaabaabbbbbbaabaabbaabaab.
	rule abbbb -> bbbbaab at position 21
.bbbbabbbbbbbbbbbbaababbbbaabbbaabaabbaabaab.
	rule abbbb -> bbbbaab at position 20
.bbbbabbbbbbbbbbbbaabbbbbaabaabbbaabaabbaabaab.
	rule abbbb -> bbbbaab at position 18
.bbbbabbbbbbbbbbbbabbbbaabbaabaabbbaabaabbaabaab.
	rule abbbb -> bbbbaab at position 17
.bbbbabbbbbbbbbbbbbbbbaabaabbaabaabbbaabaabbaabaab.