Loop of length 15 starting with a string of length 12
found after enumerating 3526 derivations:

.aaaa.aabababa
	rule aaaa -> aabb at position 0
.aabb.aabababa
	rule baab -> aaba at position 3
.aabaaba.ababa
	rule baab -> aaba at position 5
.aabaaaaba.aba
	rule aaaa -> aabb at position 3
.aabaabbba.aba
	rule baab -> aaba at position 7
.aabaabbaaba.a
	rule baab -> aaba at position 6
.aabaabaabaa.a
	rule baab -> aaba at position 5
.aabaaaabaaa.a
	rule aaaa -> aabb at position 3
.aabaabbbaaa.a
	rule baab -> aaba at position 2
.aaaababbaaa.a
	rule aaaa -> aabb at position 8
.aaaababbaabb.
	rule baab -> aaba at position 7
.aaaababaabab.
	rule baab -> aaba at position 6
.aaaabaaabaab.
	rule baab -> aaba at position 8
.aaaabaaaaaba.
	rule aaaa -> aabb at position 5
.aaaabaabbaba.
	rule baab -> aaba at position 4
.aaaaaabababa.