This article is the origin of the poetic allusion "Covering the Great Wall". If you don't understand, you can search it on Baidu~
The ending was already set before I wrote the article. I don't know how to put it, but it's very painful.
In addition, the title is inspired by Cang Yue's novel "Mirror". I thought it was suitable, so I used it.
This article is short and concise, and there are also some things that are inconsistent with historical facts and YY, so please bear with me.