WFF 'N PROOF

WFF 'N PROOF is a logic-based game created by the American mathematician and philosopher Raymond Smullyan. The game's title stands for "Well-Formed Formulae and Proof." It is designed to teach and explore concepts in formal logic and the structure of mathematical proofs. In WFF 'N PROOF, players deal with well-formed formulas (WFFs), which are specific sequences of symbols that conform to the rules of a logical language.