 Things of the same kind summon each other, those with the same vital energy join together, and sounds that match resonate. Thus if you strum a gong note other gong will resonate; if you strum a jue note other jue will vibrate. Use a dragon to bring rain; use the form to move the shadow. The masses of people think that fortune and misfortune come from fate [ming]. How could they know from where they truly come! (Chen Qiyou 1984, 20/4: 1369)