Sociologist Professor Zeng visited a lunatic asylum. He wanted to understand the living conditions of lunatics. At the end of the day, wherever he went, he saw patients acting crazy and acting unexpectedly. Professor Zeng was filled with emotion. When Professor Zeng was about to leave the asylum, he found that his tires had been removed. "Some madman must have done it!" the professor thought angrily. When he took the spare tire and prepared to install it, he found that not only the tire had been removed, but also the screws had been removed. There’s no way to get in without screws and even a spare tire! Professor Zeng looked at the car with only three tires and smiled bitterly. When he was extremely anxious, a madman jumped over and sang an unknown happy song. He spotted the professor in distress, stopped and asked what was going on.

The professor was too lazy to pay attention to him, but told him anyway out of politeness.

The madman laughed and said: "I have a way!" He removed a screw from each tire, so that he got three screws to install the spare tire.

The professor was surprised and grateful, and was very curious: "How did you come up with this method?" The madman laughed happily: "I am a madman, but I am not a fool!"