Taijitu is "two-part Taiji diagram". Unicode features the "yin-yang symbol" in the Miscellaneous Symbols block, at code point U+262F (YIN YANG ☯). The related "double body symbol" is included at U+0FCA (TIBETAN SYMBOL NOR BU NYIS -KHYIL ࿊), in the Tibetan block. The Soyombo symbol, that includes a taijitu, is available in Unicode as U+11A9E, 𑪞, U+11A9F, 𑪟, and U+11AA0, 𑪠. Ornamental patterns with visual similarity to the "yin-yang symbol" are found in archaeological artefacts of European prehistory; such designs are sometimes descriptively dubbed "yin yang symbols" in archaeological literature by modern scholars. The "taijitu" consists of five parts. Strictly speaking,
Yin and yang light; female and male; moon and sun", however, is an exception. Scholars have proposed various explanations for why "yinyang" violates this pattern, including "linguistic convenience" (it is easier to say "yinyang" than "yangyin"), the idea that "proto-Chinese society was matriarchal", or perhaps, since "yinyang" first became prominent during the late Warring States period, this term was "purposely directed at challenging persistent cultural assumptions". Needham discusses Yin and Yang together with Five Elements as part of the School of Naturalists. He says that it would be proper to begin with Yin and Yang before Five Elements because the former: "lay, as