A riddle commonly seen in novels? The answer to the riddle was "guess" and "mystery".

Many novels have riddles, usually with a word or phrase as the answer. This riddle would usually allow the reader to guess, trigger the reader's thinking and reasoning, and at the same time, increase the interest and suspense of the novel. Here was a classic riddle: Riddle: There was a man who carried a sword and wandered around the city every day without telling his address. Do you know who he is? Answer: Guessing this word is his answer. The difficulty of this riddle was that the reader could not directly know the identity and address of the person. They could only guess through his actions and words. The reader needs to think about whether this person's behavior and language have any rules to follow and what his purpose is to infer who the answer is.