What do the sixty-four hexagrams with eight diagrams symbolize?

Sixty-four hexagrams, composed of eight diagrams of heaven, earth, fire, thunder, mountain and wind, symbolize various natural phenomena and personnel phenomena. In fact, this is exactly what the ancients tried to grasp the complex natural phenomena and life phenomena through the cognitive framework of Yin-Yang gossip, which is saturated with the ancients' intuitive understanding of the laws of nature and their understanding of the essence of life, and is the crystallization of knowledge about the wisdom of nature life.