Taijitu the Tibetan designs have three or four swirls (representing the Three Jewels or the Four Noble Truths, i.e. as a triskele and a tetraskelion design), Lai Zhide's taijitu has two swirls, terminating in a central circle. The Ming-era design of the taijitu of two interlocking spirals has been reported as "yin-yang symbol" in the first half of the 20th century. The flag of South Korea, originally introduced as the flag of Joseon era Korea in 1882, shows this symbol in red and blue. This was a modernisation of the older (early 19th century) form of the Bat Quai Do used
Dualistic cosmology able to transmute into each other. In the yin-yang symbol there is a dot of yin in yang and a dot of yang in yin. In Taoism, this symbolizes the inter-connectedness of the opposite forces as different aspects of Tao, the First Principle. Contrast is needed to create a distinguishable reality, without which we would experience nothingness. Therefore, the independent principles of yin and yang are actually dependent on one another for each other's distinguishable existence. The complementary dualistic concept seen in yin and yang represent the reciprocal interaction throughout nature, related to a feedback loop, where opposing forces do