Yin and Yang

 In Chinese concept, yin and yang are two opposing elements of the universe. They are not two poles like good and evil, however; they are relative. For example,

          Yin: associates with the dark Moon (facing away from Sun), represents feminine nature
          Yang: associates with the bright Sun, represents masculine nature

Yin and yang can also be used (in conjunction with other characters) to indicate various parts of the male and female anatomy.

A modern example:

          Yin: the traffic light on the freeway (the stillness)
          Yang: the traffic that flows past that traffic light (the vivaciousness)

Some Chinese, Korean and Japanese place names that still exist are named in the following principle: 

        Yin: the north side of the mountain, the south side of the river. 
        Yang: the south side of the mountain, the north side of the river.&nbs