The symbol above has a Chinese origin. It is called Taijitu but has come to be known as the yin and yang symbol It is beautiful and simple. It represents everything about life on earth.
Inside the circle, there is white half and a black half. Inside each half there is a dot of the opposite colour. The white half is known as yang and the black half as ying.
The yin is the negative force. In the natural world, the moon, cold, earth, growth, subtle, feminine, calm, slow, curvy, old, dirty, textured and small, while the yang is the sun, hot, heaven, generation, loud, masculine, bold, fast, straight, new, clean, plain and big.
The symbol tells us that they are two elements in the circle of life. It is interconnected, interdependent and interrelated. One gives rise to another. One gains its value, its meaning, its usefulness from the other. The day begins after the night. There is no if there is no ugliness, no rich without the poor, nothing is fast if there is nothing slow. The yin and yang symbolizes the wholeness of existence.
The dot in the opposing colour inside each half is a reminder that there is an element of the other inside each. A little yin inside of yang and a little yang inside of yin. A positive in the negative and negative in the positive. Nothing is totally good. Nothing is totally bad. Too much of a good thing can be a bad thing. Drinking plain water is generally accepted to be good, but drinking too much can be poisonous to the body. Alcohol is generally accepted as toxic to the body but a little alcohol has been shown to be beneficial.
The yin and yang is not static. It flows towards one another. The day flows into the night. The moon slowly disappears as the sun comes to the horizon.
Another aspect of the opposing nature of this world is when we start something; there is always a force against it. When you plan to wake up early and get some exercise done, you will always feel the urge to just hit the snooze button and pull-up the blanket. For every act you plan to do, you can be sure there will a force against it. That is the nature of things. That is yin and yang. The yin and yang philosophy is deep and you can read about it more here.