This symbol represents the Light to Dark balance, and the dot in the middle of each side signifies that you cannot have one without the other. Yin is the morning sun; Yang is the nighttime moon. Yin is the rushing waterfall; Yang is the slow-moving river. Yin is the speedy runner; Yang is the lazy napper. Those are just some examples of Yin and Yang, but you cannot have one without the other, even if there is a small difference.