The WFF games (Shake-a-WFF and Count-a-WFF) are the first two in a series of 21 games called WFF 'N Proof. The two WFF games are concerned with the construction of WFFs (well formed formulas). A WFF (pronounced "woof") is a expression in a system of mathematical logic that is roughly equivalent to a sentence in English prose. In the WFF games, certain sequences of letters are considered WFFs, and players attempt to arrange an increasing number of letter dice to create ever-longer true sentences, or WFFs. In Shake-a-WFF, the two players practice recognition and construction of WFFs. Players use six capital-letter dice, six small-letter dice, and a Shake-a-WFF playing mat (one mat each). Each player begins with three dice, and seeks to create a WFF using the letters they've rolled. Each round, players add or subtract a die from their shaking set according to whether they successfully created a WFF in the previous round or not. The first player to create a WFF with eight dice wins the game. In Count-a-WFF, two or more players simultaneously view the same set of rolled dice to try to create the longest single WFF from the letters rolled. Each player attempts to maximize their score for a specified number of plays; the player with the highest score wins. The game includes 12 special lettered dice, 2 Shake-a-WFF player mats, and a 78-page rules and examples manual.