A professor had this lie detecting chair. Whenever anybody sitting on it would tell a lie, the chair would open up and the person would fall flat on the ground. So in his experimentation a young brunette came in and sat down. The professor asked her to tell about herself. She began, "I think I'm the most beautiful girl in this region, and perhaps even in the whole world!", immediately after saying that the chair opened up and she landed flat on her ass. She stormed out, at which time a young blonde was invited in to sit. She sat down and was invited to tell about herself. She began, "I think", and suddenly the chair opened up and she fell flat on her ass!