Yin Yang

The ancient Chinese subscribe to a concept called Yin Yang which is a belief that there exist two complementary forces in the universe. One is Yang which represents everything positive or masculine and the other is Yin which is characterized as negative or feminine. One is not better than the other. Instead they are both necessary and a balance of both is highly desirable.
You will notice that in Yang (represented by the white tadpole) lies the seed of Yin (represented by the black dot) and vice-versa. In the study of Chinese medicine, we are well when the Yin and Yang of our body is in a state of balance. But when the body body goes out of balance or when when there is too much Yin or Yang, we fall sick. The aim is to keep the body in balance. This is the basic Yin Yang concept. This is why watermelon is consumed in Summer while double boiled soup is taken in winter. Watermelon has a cooling effect and it serves to cool the body during the hot summer months. In Winter, the hot double boiled soup provide balance by warming the body. Here goes. Yin is soft while Yang is hard. Yin is stillness while Yang is movement. The sun is yang while the moon is yin. Female is Yin while Man is Yang. Mountain is Yin while the river is Yang. Intuitive is Yin while Logical is Yang. Winter is Yin while Summer is Yang and so on.