Riddle: There once was a man who was very smart. when the police caught him spying on the president they said that he could have one last time to say something. "If what you say is false you will be shot", said the police officer,"and if what you say is true, you will be hung." Then the man said," I will be shot." what will be his fate?
Answer: He can't be punished because if he was shot then he would be hung but then what he said would be false. His punishment could not be possible so he was let go.