The Origin of Tai Chi Diagram (used to be translated as the Diagram of the Universe)——Yin and Yang. Here is the picture showing how the ancient genius study the movement of the sun and how do they draw the diagram of Yin-Yang originally（A sketch map of the mechanism of  a sundial）.

      Many people who are fond of Chinese culture have seen the Diagram of Tai Chi, which was used to be translated as the diagram of the universe  .  Tai Chi is composed of  Yin and Yang, which evolve and fuse as one, represented by the more commonly-seen but modified double-fish-like Tai Chi symbol. However, the original Tai Chi symbol is a masterpiece of the ancient Chinese astronomists and cosmologists.  The concepts of Yin-Yang, Tai Chi and Tao/Dao are, in fact,  all deeply rooted into the ancient Chinese cosmology and astonomy.  As they build theories about the sun, the moon, the earth,  the living things and the universe, they finally established theories about how the universe gives birth to the human beings and all living things on earth,  explained the relationship between the living mortals and the imortal universe, and studied  how the universe interacts with the earth and its residents, living beings. Based on the knoledge of this , they established the Basic theories of Chinese medicine.