So he set out to devise a game that was half luck, half skill. And by the end of 1931 he had developed the initial idea for the game, which he called Lexico.

Lexico was played without a board and players scored on the basis of the lengths of the words formed. There were additional scores for words employing 'minor honours' (B, F, H, M, P, V, W, Y) and a higher additional score for major honours (J, K, Q, X, Z).

Butts calculated the letter frequency and value of each letter of the alphabet by meticulously combing the front page of the New York Times.

He reasoned that too many S's made the game too easy. So he reduced them to 4.