Smullyan

Puzzles

• black.hatThree logicians, A, B, and C, are wearing hats, which they know are either black or white but not all white.
• cannot.tellA knight always tells the truth, and a knave always lies. New
• electionA Meta-Puzzle: who was the Mathematician, who the Philosopher, who was Normal, and in what order did they... New
• equivocatorOn the way to Heaven you meet a person who sometimes tells the truth and sometimes lies. New
• fork.three.menThree men stand at a fork in the road. Added material
• fork.two.menTwo men stand at a fork in the road. Added material
• integersTwo logicians place cards on their foreheads so that what is written on the card is visible only to the other logician.
• kings.daughterOn an island of knights (who always tell the truth), knaves (who always lie) and normals (who may do... New
• liars.et.alOf a group of n men, some always lie, some never lie, and the rest sometimes lie. Restored
• marry.non.normalYou wish to marry the daughter of the king of the Island of Knights, Knaves, and Normals. New
• painted.headsWhile three logicians were sleeping under a tree, a malicious child painted their heads red.
• priestIn a small town there are N married couples in which one of the pair has committed adultery. Added material
• rattlePuzzle 61 in R. Smullyan's _What is the Name of This Book?_ is about Tweedledum and Tweedledee. New, unsolved
• stampsThe moderator takes a set of 8 stamps, 4 red and 4 green, known to the logicians, and loosely affixes two... Added material
• three.menOf three men, one always lies, only never lies, and one sometimes lies. Restored
• two.fifths.truthfulOn a certain island, everyone is either a truth-teller or a liar. New