The Five Elements are Metal, Wood, Water, Fire, and Earth. In ancient times, Chinese people believed that the entire universe was composed of these Five Elements. The elements are structured in two overlapping cycles: the Constructive Cycle and the Destructive Cycle. In the Constructive Cycle, the relationship between two elements is positive, where the presence of one element nurtures the development of the other. In the Destructive Cycle, the relationship between two elements is negative, where the presence of one element diminishes or weakens the power of the other. The theory of the Five Elements contributed to the development of the ancient Chinese fields of philosophy, medical sciences, astronomy, and geography.