Chu Ke chose it because it illustrates the "yin" and the "yang," the Chinese concept of opposites, such as man and woman, sun and moon, heaven and earth, and positive and negative.
楚戈指著圖案說：「當中的雙蛇造型一致，但卻以不同的花紋顯示雌雄之別，代表陰陽、天地的觀念，中國的太極圖可說是由此脫胎而來。」