A yin yang symbol is the perfect fusion of opposition and balance, primary components of the art of feng shui.

Think of it as male and female, light and dark, good and evil; these are just a few of the concepts encompassed by the ancient yin yang symbol. Although each half is teardrop shaped, they fit perfectly together. The small circle in each teardrop represents the philosophy that yin and yang each originate from the other. Today, great license is taken with this design by the popular media. See a few examples right here.
Equalibrium