Pete (australian) performing Ba gua in Qufu Shaolin Martial Arts School. Ba Gua Zhang is recognized as one of the three orthodox "internal" styles of Chinese martial art (the other two being Xing Yi Quan and Tai Ji Quan). Ba Gua literally translates to Eight trigrams. These trigrams are symbols which are used to represent all natural phenomena as described in the ancient Chinese text of divination, the Book of Changes (Yi Jing).
Taiji, the "Supreme Ultimate" state of undifferentiated absolute and infinite potential is the oneness before duality; from here Yin and Yang originate. (Guide to the I Ching, China's most popular means of divination)
This is a Yin-Yang, a symbol of Daoism. It is surrounded by 8 symbols, separated by season, and direction. The 8 symbols stand for different elements of the world, and all relate to the natural order of things.