This is "the first spring of the desert", as the ancient poem says "the sand and wind whistle, the spring reflects the moon and has no dust". A curve is like the beginning of the lunar system, and the half-wall mirror is clear. Wind and sand can't fly, water stops in the deep are interacting with each other. Looking at the moon in the desert, without light pollution and building shelter, climbing up the sand dunes, you will feel that you can see the huge moon, but also the stars in the sky as the background.