Loop of length 30 starting with a string of length 13
found after enumerating 1153 derivations:

.aaaa.aabababab
	rule aaaa -> abab at position 0
.abab.aabababab
	rule baab -> aaba at position 3
.abaaaba.ababab
	rule baab -> aaba at position 5
.abaaaaaba.abab
	rule aaaa -> abab at position 3
.abaababba.abab
	rule baab -> aaba at position 1
.aaabaabba.abab
	rule baab -> aaba at position 3
.aaaaababa.abab
	rule baab -> aaba at position 7
.aaaaabaaaba.ab
	rule baab -> aaba at position 9
.aaaaabaaaaaba.
	rule aaaa -> abab at position 7
.aaaaabaababba.
	rule baab -> aaba at position 5
.aaaaaaabaabba.
	rule aaaa -> abab at position 3
.aaaababbaabba.
	rule baab -> aaba at position 7
.aaaababaababa.
	rule baab -> aaba at position 6
.aaaabaaabaaba.
	rule baab -> aaba at position 8
.aaaabaaaaabaa.
	rule aaaa -> abab at position 6
.aaaabaababbaa.
	rule baab -> aaba at position 4
.aaaaaabaabbaa.
	rule aaaa -> abab at position 2
.aaababbaabbaa.
	rule baab -> aaba at position 6
.aaababaababaa.
	rule baab -> aaba at position 5
.aaabaaabaabaa.
	rule baab -> aaba at position 7
.aaabaaaaabaaa.
	rule aaaa -> abab at position 5
.aaabaababbaaa.
	rule baab -> aaba at position 3
.aaaaabaabbaaa.
	rule aaaa -> abab at position 1
.aababbaabbaaa.
	rule baab -> aaba at position 5
.aababaababaaa.
	rule baab -> aaba at position 4
.aabaaabaabaaa.
	rule baab -> aaba at position 6
.aabaaaaabaaaa.
	rule aaaa -> abab at position 4
.aabaababbaaaa.
	rule baab -> aaba at position 2
.aaaabaabbaaaa.
	rule baab -> aaba at position 4
.aaaaaababaaaa.
	rule aaaa -> abab at position 9
.aaaaaabababab.