《文心雕龙·定势》
所以总括各种体势，其功效在于权衡辨别，像音乐有宫商五音，色彩有朱紫五色般，文章要随体势变化调配。
是以括囊杂体，功在铨别，宫商朱紫，随势各配。
Therefore, when summarizing various styles, the effect is to weigh and distinguish them, like how music has five tones of gong, shang, jiao, zhi, yu, and colors have five colors of red, purple, and blue.