Yin and Yang are the two opposite but yet interdependent energies of life. Each is relative to one another, and can't exist without the other. They arise from a common source, the Tao. Our entire physical reality is based on the interplay of these two energies. http://fractalenlightenment.com/24816/culture/yin-yang-a-symbol-of-balance-and-harmony
The black and white halves of the Yin-Yang symbol are similar to the two sides of a coin. They are different, and distinct, yet one could not exist without the other. The circle itself - which contains these two halves - is like the metal of the coin. It is what the two sides have in common - what makes them "the same."
World Religion Colorful Icons by Roberto1977, via Dreamstime: I thought this would be good to repin because I did not even know what all of these represented & as parents I believe we need to be aware. Maybe this is naive, but I had no idea that the ying & yang symbol was a religious symbol, although I had heard of Taoism.