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 a mountain and a valley. Yin (literally the 'shady place' or 'north slope') is the dark area occluded by the mountain's bulk, while yang (literally the "sunny place' or "south slope") is the brightly lit portion. As the sun moves across the sky, yin and yang gradually trade places with each other, revealing what was obscured and obscuring what was revealed. Yin is characterized as slow, soft, yielding, diffuse, cold, wet, and passive; and is associated with water, earth, the moon, femininity, and night time. Yang, by contrast, is fast, hard, solid, focused, hot, dry, and active; and is associated