In the Huainanzi, a man skilled in divination lives near the frontier. His horse runs off to the nomads. People console him. His father says: “How do we know this is not good fortune?” Months later, the horse returns with a fine nomad horse. People congratulate him. The father says: “How do we know this is not misfortune?” The son loves to ride, falls and breaks his thigh. The father says again that it may be good fortune.
A year later, the nomads invade. The able-bodied men take up their bows and fight, and nine in ten of the people near the frontier die. Because he is lame, the son is spared. “Fortune turns into misfortune, and misfortune into fortune. The changes have no end, and their depth cannot be measured.”