Rafters: wooden cases; Pearl: Pearl. Bought a business box and returned the pearls. Metaphor is a person who has no vision, improper choice, and only pays attention to appearance but not substance. It also satirizes those who don't understand the essence of things, abandon the roots and pursue the end, and abandon the Lord for the second time.
From Han Fei's "Han Fei Zi Wai Chu Upper Left".
The story says: There was a jeweler in the State of Chu who went to the State of Zheng to sell jewelry. He made a box out of Mulan, fumigated it with spices made of cinnamon and pepper, decorated it with beautiful jade, and connected it with kingfisher feathers. A Zheng bought a box, but returned the beads in the box to the Chu people. This man is good at selling boxes, not beads.