An alphabet ring is formed if the 26 letters of the alphabet are written down (in any order) on the circumference of a circle, so that each letter has a predecessor and a successor. This article describes several logological studies based on such rings.
Eckler, A. Ross
"Alphabet Rings of Trigrams,"
Word Ways: Vol. 10
, Article 16.
Available at: http://digitalcommons.butler.edu/wordways/vol10/iss3/16