The May 1973 issue of Word Ways introduced the concept of a word network, a connected diagram of words of a single length, in which any two words differing in only one letter in the same position (as BRA and ERA, or TON and TEN) are joined by a line. Networks with more than 50 or 100 words are generally too complicated to diagram on a single sheet of paper, and it is difficult to assess their properties.
Eckler, A. Ross
"The Growth of a Word Network,"
Word Ways: Vol. 22
, Article 5.
Available at: http://digitalcommons.butler.edu/wordways/vol22/iss2/5