This building we're in has doors and windows. If we close the doors and windows, we can't get out. People lock themselves inside a house of delusions. But they're only delusions. They can leave anytime. Actually there is no house to leave. There's not even any leaving. What we see are flowers in the sky, the moon in the water. As for the meditative powers of Zen masters like Hsu-yun, sometimes it's useful to meditate and sometimes it isn't.