wff- beginner's game of modern logic 1966 edition. designed by layman e. allen, publisher, wff n proof games. enclosed are the first two games in a series of 21 games, these games are, shake-a-wff and count-a-wff. WFF stands for the object of the game Well Formed Formulas. the complete games include 12 special lettered dice however this game comes with 8 dice, 4 missing, 2 shaker mats and 78 page rules and examples manual, which has former holders name stamp in first page and cardboard holder is cracked with wear.