Considered as a whole, the ultimate meaning of the yin yang symbol can be interpreted as one of universal balance and harmony.
Think of a yin yang symbol and the yin side pushing while the yang side pulls.
In the Chinese culture, especially in feng shui practices, the yin yang symbol signifies the koi fish with its ever watchful eye on the world.
The yin yang philosophy states that the two energies combine to form the perfect energy of chi, which is found in all living matter.
For example, if you have two big cakes and lots of cupcakes, use the cakes as dots inside a yin-yang symbol, and fill out the rest of the design with the cupcakes.