The above diagram is called the Tai Chi Tu, The Supreme Ultimate Principle and Truth of the Universe. More than just representing duality and how opposite forces check and balance each other, the Taichi symbol was also meant to be gently gazed at while in a state of meditation. Through-out the different stages of life, the ancient Taoist used this "gazing" practice to them help unlock its subtle non-verbal truths of the universe.
Composed of Yin-Chi (Feminine-Energy, Earth, Softness, Water) and Yang-Chi (Masculine-energy, Heaven, Firmness, Fire) the essence of Tai Chi principle is all about balance. It is at the very center of how all living things manifest and function in the universe.
According to the great Taoist Sage, Lao Tzu, all life exists and thrives because of the interaction between Yin and Yang. These two energy poles are in a constant state of struggle and opposition to each other, and yet mysteriously, they always manage to harmonize and balance each other out...since, the ebbing and flowing of they're spiraling dance was never seperate to begin with.