Why did Tomb-Sweeping Day hang paper on the tomb?

Qin Shihuang needed many bricks and stones to build the Great Wall of Wan Li. The Great Wall was soon repaired. Bricks can't burn, and stones can't be dug. Qin Shihuang issued an imperial edict to remove all the bricks and stones from the tomb and carry them to repair the Great Wall. At that time, Qin Shihuang's father had just died a few days ago. If the grave is dug, so will his father's grave. Where's Chawu? He called the minister who dug the grave to him and said, "Don't dig the marked grave." According to the custom, after burying a person, it is called inserting a coffin in a new grave. Soul guides are all cut with white paper, swaying with the wind in the new grave, which is very eye-catching Ministers who were digging graves went to Qin Shihuang's father's grave and saw a piece of white paper hanging, thinking it was a sign, so they stopped digging graves. When people saw white paper hanging on the grave, they cut it out and hung it on the grave when they went to the grave. In this way, handed down from generation to generation, has become a custom. The last note told by Wu 1. What should I do? 2 eye-catching: eye-catching.