 To the Yijing commentators, the unfolding of the universe is vividly portrayed in the 8 trigrams and 64 hexagrams. For instance, they see the 8 trigrams (☰, ☱, ☲, ☳, ☴, ☵, ☶, ☷) as graphic representations of the mixing of the yin and yang cosmic forces (or qi, energy). With different combinations of a straight line (—) representing the yang cosmic force, and a broken line (‒ ‒) representing the yin cosmic force, a trigram symbolizes the cosmos’ constant renewal and its creation of the myriad things. Similarly, a hexagram is also a symbol of the unfolding of the universe. For example, a hexagram can be divided into two trigrams: the lower trigram (lines 1–3) and the upper trigram (lines 4–6). With two trigrams, a hexagram symbolizes the interaction of two sets of yin-yang configuration, demonstrating the multiple ways in which the yin and yang forces interact and transform each other. Or, one takes the lower two lines of a hexagram as representing the earth (di), the middle two lines as representing humankind (ren), and the top two lines as representing heaven (tian). Then, we have a trigram within a hexagram. Known as the “three potencies” (san cai), the relation of heaven, earth, and humankind highlights the co-dependence between the natural realm (tian and di) and the human realm (ren).