In fact, it gives me the feeling that the whole book of changes is about yin and yang. One yin and one yang are called Tao, and they are all yin and yang in different environments. Sixty-four hexagrams have changed a lot, and the truth is endless. For physical conditioning, it is to meet your own needs for yin and yang, adjust your balance of yin and yang in different adverse situations, and adapt yourself to the environment. Yin and Yang are all things, so there are various ways to use them.