Zen parable retold in ASL. See the links in the right column.
A university professor went to visit a Zen master. While the master served tea for the guest, the professor talked and talked about Zen. The master quietly listened and poured the cup to the brim, but he didn't stop. He kept pouring and the cup was overflowing.
The professor watched the overflowing cup until he could no longer restrain himself. "Hey, it's overfull."
The master was aware, "Your mind is like this cup. If I teach you Zen, you mind will overfill it. How can I show you Zen if you have not emptied your mind first?"
"One needs to deconstruct one's belief before relearning new a perspective."
Also see The Moving Mind: a Zen parable.