In a companion article, the editor estimates the number of m-letter words to be drawn at random from the dictionary in order to have a reasonable expectation of forming an mxm word square. This is a task admirably suited to the computer, which can take a list of words and check all possible combinations for potential squares.
"Common 4x4 Wordsquares,"
Word Ways: Vol. 25
, Article 3.
Available at: http://digitalcommons.butler.edu/wordways/vol25/iss2/3