At the center, Yin and Yang. These dichotomous energies (dark, light; centripetal, centrifugal; in, out) swirl endlessly, generating our ouniverse. Each is becoming the other. Note the solid and broken lines. These are used in “throwing the changes,” a form of divination as found in the I Ching. You used yarrow sticks and the patterns showed the state of things and thus could give advice.