Yin-yang is an active concept: yin and yang are thought to arise together from an initial quiescence or emptiness (wuji, sometimes symbolized by an empty circle), and to continue moving in tandem until quiescence is reached again. For instance, dropping a stone in a calm pool of water will simultaneously raise waves and lower troughs between them, and this alternation of high and low points in the water will radiate outward until the movement dissipates and the pool is calm once more. Yin-yang, thus, always has the following characteristics Go to site for more information.

Yin and yang, the perfect couple.