It's called a magic box. The music is really "Yan Ming's Elegy". The production of the magic box is wonderful and absolutely extraordinary. It looks just like an ordinary music box outside, with the words of Chu on the box surface: "The magic law is twelve, the five tones are not music, the bliss is heavenly, and the magic sounds are myriad." After the pavilion was built according to the five tones and twelve laws, the gears of the internal organs turned, making it appear as a tower-shaped pavilion. The pavilion has five floors, each of which corresponds to the five tones of "Gong, Shang, Jiao, Zheng and Yu" (the first floor is feather tune). There are twelve cornices on each floor, and there is a window under each cornice. Each window is marked with the name of the melody, which corresponds to the twelve laws.