Taijitu is still. In stillness it generates "yin"; yet at the limit of stillness it is also active. Activity and stillness alternate; each is the basis of the other. In distinguishing "yin" and "yang", the Two Modes are thereby established. The alternation and combination of "yang" and "yin" generate water, fire, wood, metal, and earth. With these five [phases of] "qi" harmoniously arranged, the Four Seasons proceed through them. The Five Phases are simply "yin" and "yang"; "yin" and "yang" are simply the Supreme Polarity; the Supreme Polarity is fundamentally Non-polar. [Yet] in the generation of the Five Phases, each one
Yin and yang contracting) are thought of as physical manifestations of the duality symbolized by yin and yang. This duality lies at the origins of many branches of classical Chinese science and philosophy, as well as being a primary guideline of traditional Chinese medicine, and a central principle of different forms of Chinese martial arts and exercise, such as baguazhang, taijiquan (t'ai chi), and qigong (Chi Kung), as well as appearing in the pages of the "I Ching". The notion of a duality can be found in many areas, such as Communities of Practice, but in this context yin and yang are better