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
School of Naturalists and Qi. In later periods, these epistemological theories came to hold significance in both philosophy and popular belief. This school was absorbed into the alchemic and magical dimensions of Taoism as well as into the Chinese medical framework. The earliest surviving recordings of this are in the Ma Wang Dui texts and Huang Di Nei Jing. Zou Yan (; 305240 BC) was an ancient Chinese philosopher best known as the representative thinker of the Yin and Yang School (or School of Naturalists) during the Hundred Schools of Thought era in Chinese philosophy. Zou Yan was a noted scholar of the