Chinese sun and moon mirrors being hung round the neck, or because necks are concave things. Liu An's (c. 139 BCE) "Huainanzi" "Masters of Huainan", which is a compendium of writings from various schools of Chinese philosophy, was the first text to record "fangzhu" dew-collectors. Two "Huainanzi" chapters metaphorically use "sun and moon mirrors" to exemplify "yang" and "yin" categories and elucidate the Chinese notion of "ganying" "cosmic resonance" through which categorically identical things mutually resonate and influence each other. The "yángsuì" 陽燧 "burning-mirror" is "yang", round, and sun-like; the "fāngzhū" 方諸 "square receptacle" is "yin", square, and moon-like. The first context describes "yangsui" and
Yin and yang for complex depictions of interrelations. The principle of yin and yang is represented in Taoism by the Taijitu (literally "Diagram of the Supreme Ultimate"). The term is commonly used to mean the simple "divided circle" form, but may refer to any of several schematic diagrams representing these principles, such as the swastika, common to Hinduism, Buddhism, and Jainism. Similar symbols have also appeared in other cultures, such as in Celtic art and Roman shield markings. Taijiquan (Chinese: 太极拳), a form of martial art, is often described as the principles of yin and yang applied to the human body and an