It is called "Purple Stopper" because there is a lot of purple soil near the Great Wall. Yanzhi, that is, rouge, deep red. Here it is written that under the sunset, the soil is like a swallow's fat, and the purple color is even more vivid. In fact, we were both wrong, both sentences can be used! But the more commonly used one is stuffed with Yanzhi Ningye Zi! When the governor of Yanmen was on his way, black clouds pressed down on the city, threatening to destroy it, and the light of armor opened towards the golden scales of the sun. The sound of the trumpet fills the autumn sky, and the swallow's fat condenses into purple at night. A half-rolled red flag stands near the Yishui River, but the sound of heavy frost and cold drums cannot be heard. I will report to you on the golden platform and support the jade dragon to die for you.