Talk about the meaning of this sentence, which contains the author's feelings.

The "Zheng Peng" who went with the wind and the "returning geese" who entered the lake field are also the portrayal of the poets who went to the frontier fortress. The poet compares himself with "Peng" and "Yan", revealing the poet's unspeakable anger and anguish.

I floated out of Sai Han like a disorderly grass, and entered the lake field like a "wild goose" flying north. In ancient poetry, flying over the eaves and walking over the wall is often used as a metaphor for a wandering wanderer, but here it is a metaphor for a minister with a court mission, who is secretly writing the poet's inner anger and depression. It echoes the "bicycle" in the first sentence. The trip to Wan Li took only ten words. ........