What do the eight hexagrams in the Book of Changes stand for?

According to this ancient philosophy and the thought of destiny at that time, astronomers and fortune tellers at that time compiled the Book of Changes, which developed the gossip handed down from generation to generation in Fuxi into a set of all-encompassing and mysterious theories. In the eight diagrams, one represents yang, one represents yin, one represents heaven (dry), one represents earth (Kun), one represents water (ridge), one represents fire (separation), one represents thunder (earthquake), one represents mountain (root), one represents wind (smoke) and one represents swamp (exchange).