Thirty spokes unite in one hub; it is the hollow that makes the wheel useful. Clay is shaped into a vessel; it is the emptiness that makes the vessel useful. Doors and windows are cut to make a room; it is the space within that makes it useful. Therefore, what is there gives form, but what is not there gives use. ----- All conditioned things are impermanent; when this is seen with wisdom, one turns away from suffering. This is the path to purity. All conditioned things are suffering; when this is seen with wisdom, one turns away from suffering. This is the path to purity. All phenomena are without self; when this is seen with wisdom, one turns away from suffering. This is the path to purity.