Man in green says, "the man in yellow is a knave. " Man in yellow says, "we are both knights. " Both men are knights: contradictory because green says yellow is knave. Both men are knaves: contradictory because green"s statement would be true. Green is knave and yellow is knight: contradictory because yellow says that both are knights. Green is knight and yellow is knave: consistent as green is truther and yellow is liar. Two clowns stand at a fork on the road; one is a knight and the other is a knave; one stands in front of a safe path while the other stands in front of the path to doom. Ask one single "yes" or "no" question to find which path is safe. Asking a single yes/ no questions is essentially equivalent to asking the truth value that is associated with declarative statement but you do not need to know whether the clown you ask is a knight or knave.