The Chinese believe everything that exists has chi and in turn, everything that has chi has yin qualities and yang qualities. Yin and yang are opposites and complementary- one cannot exist without the other.
One teardrop embodies yin qualities, which are soft, passive, nurturing, dark, fluid, even numbers and the right side of the body. The other teardrop signifies yang traits, which are male, bright, hard, active, aggressive, odd numbers and the left side of the body. The two halves comprise a whole, yet there is an element of each in the other.
A fluid S-shaped line divides the two teardrops and represents the balance within the universe, nature, the environment and the self. To achieve good chi in feng shui the yin and the yang have to be balanced. Achieving this balance results in feeling grounded.