In the world of children's humor, the riddle is the dominant form, and many of us grow up riddling into adult life. Most riddles involve a play on words. (Some would say a prey on words.) "What's black and white and read all over? A newspaper!" has been for several generations the first riddle that English speakers learn. Such question-and-answer interaction represents the child's first awareness that two or more meanings can occupy the same verbal space at the same time.