The I Ching illustrates the same trigram layout that is depicted on the flag. It shows the eum-yang symbol in the center and trigrams on the sides, but it shows eight trigrams. The other trigrams are "mountain" and "lake", and "thunder" and "wind." Each of the trigrams has a special meaning and are either eum or yang. Heaven and lake are major yangs; water and wind are minor yangs. Earth and mountain are major eums; thunder and fire are minor eums. Originally, there were only five trigrams, one for each of the five elements: water, metal, fire, wood, and earth. They were arranged like a compass, with earth in the center, metal on the left, wood on the right, water at the top, and fire at the bottom.