Shang Tang Music in Sanglin Legend and Yao Music in Jing Shou Legend. This sentence means to describe doing things with rhythm and beauty. Zhuangzi's "Health Master". My ingenious knowledge of cows said: "My ingenious knowledge of Wen Niu, the touch of hands, the leaning of shoulders, the shoes of feet, the position of knees, the natural direction and the natural tone of knives are the first of the classics. In other words, in the process of killing cattle by skilled workers, whether they are dancing with knives or axes or walking arm in arm, they are as beautiful and rhythmic as dancing. These two sentences are quoted from famous songs to describe this aspect. You can learn from it.