What is the metaphor of Cao Peng in ancient poems?

A state of wandering, wandering and helplessness. Pennisetum is a kind of weeds that grow on grasslands or fields. Because of its lush growth and lightness, it is often used to symbolize the vagaries of life. In ancient poetry, grass is often associated with images such as migration, exile and loneliness. Through Peng Cao's metaphor, the poet expressed his own or others' sadness of leaving their homes and being displaced, or expressed his feelings and thoughts on the passage of time and the changes of the world.