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
Tai chi single ultimate, represented by the "taijitu" symbol . Tàijíquán theory and practice evolved in agreement with many Chinese philosophical principles, including those of Taoism and Confucianism. Tàijíquán training involves five elements, "taolu" (solo hand and weapons routines/forms), "neigong" and "qigong" (breathing, movement and awareness exercises and meditation), "tuishou" (response drills) and "sanshou" (self defence techniques). While tàijíquán is typified by some for its slow movements, many styles (including the three most popular: Yang, Wu and Chen) have secondary forms with faster pace. Some traditional schools teach partner exercises known as "tuishou" ("pushing hands"), and martial applications of the postures of