The deaf joke about the dumb.

The fool smells the perfume on the madman.

The vivid feature of this couplet is that fools can't perceive the external information through hearing or vision, but only rely on the sense of smell to perceive the surrounding environment, while lunatics do some behaviors that are difficult for ordinary people to understand because of mental disorders, such as wearing perfume. This strong contrast and contrast make this bottom line look very interesting and humorous.

Note: this bottom line is purely entertainment, and there is no intention to attack or belittle deaf, visually impaired or mentally retarded people.