A transposal square is a square array of letters in which each row and column can be rearranged to form a word. Philip Cohen introduced the concept to Word Ways readers in his November 1979 Kickshaws, presenting there a 10-by-10 double transposal square (ten distinct letter-combinations arrangeable into words in the rows, and ten additional distinct letter-combinations arrangeable into words in the columns). This article exhibits a 12-by-12 double transposal square produced by his construction method, as well as an 11-by-11 single transposal square.
Eckler, A. Ross
"Single and Double Transposal Squares,"
Word Ways: Vol. 13
, Article 3.
Available at: http://digitalcommons.butler.edu/wordways/vol13/iss2/3