An interesting Link for the study of Yin Yang.
Yin and Yang
The yin and yang represent all the opposite principles one finds in the universe. Under yang are the principles of maleness, the sun, creation, heat, light, Heaven, dominance, and so on, and under yin are the principles of femaleness, the moon, completion, cold, darkness, material forms, submission, and so on. Each of these opposites produce the other: Heaven creates the ideas of things under yang, the earth produces their material forms under yin, and vice versa; creation occurs under the principle of yang, the completion of the created thing occurs under yin, and vice versa, and so on. This production of yin from yang and yang from yin occurs cyclically and constantly, so that no one principle continually dominates the other or determines the other. All opposites that one experiences—health and sickness, wealth and poverty, power and submission—can be explained in reference to the temporary dominance of one principle over the other. Since no one principle dominates eternally, that means that all conditions are subject to change into their opposites.
Richard Hooker – http://www.wsu.edu:8080/~dee/CHPHIL/YINYANG.HTM