Taijitu during the Qing period for their possible connection with Zhou Dunyi's "taijitu". Ming period author Lai Zhide (1525–1604) simplified the "taijitu" to a design of two interlocking spirals. In the Ming era, the combination of the two interlocking spirals of the "taijitu" with two black-and-white dots superimposed on them became identified with the "He tu" or "Yellow River diagram" (河圖). This version was reported in Western literature of the late 19th century as the "Great Monad", and has been widely popularised in Western popular culture as the "yin-yang symbol" since the 1960s. The contemporary Chinese term for the modern symbol
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