The word worm was introduced to readers of Word Ways by Ross Eckler in an article of the same name in the August 2003 issue (p.13). Word worms are based on the three-dimensional lattice of integer-valued points.
"Accidental Ouroboros Word Worms in Running Text,"
Word Ways: Vol. 45
, Article 7.
Available at: http://digitalcommons.butler.edu/wordways/vol45/iss3/7