The Book of Changes and its eight gates

Before there were sixty-four hexagrams there were eight trigrams, the bagua, three lines each, every line either whole (yang) or broken (yin). Eight ways three coins can fall. The legend gives them to Fuxi, who is said to have read them off the back of a dragon-horse rising from the river, which is a poet's way of saying someone, a very long time ago, looked hard at the world and found eight basic weathers in it.

Heaven, three whole lines, pure yang, the creative, the sky, the father. Earth, three broken lines, pure yin, the receptive, the field, the mother. And between those two poles the other six, each a different mix, each a family member, each a force. Thunder, the arousing, the eldest son, the shock that wakes you. Water, the abysmal, the middle son, the danger and the deep. Mountain, stillness, the youngest son, the place you stop. Wind, the gentle, the eldest daughter, the thing that gets in everywhere. Fire, the clinging, the middle daughter, brightness that needs fuel to hold on. Lake, the joyous, the youngest daughter, the open mouth, the marsh, delight.

Stack two trigrams and you get a hexagram, and there are sixty-four of those, and that is the Book of Changes, the I Ching, the thing people have thrown coins and yarrow stalks at for three thousand years. But the point of it was never fortune-telling the way a carnival means it. The point was a mirror. You bring a real question, you let the lines fall, and the hexagram they make is not a prediction, it is a description of the shape of this moment, and the moment, like all of them, is already changing, which is the whole book's name.