Two Zen monks, a young and a patriarch, walk on a desert plateau. The young appointed asks: "Master, I want to know what is the secret, what is the silence?" The patriarch remains silent and continues on its way, followed by the young disciple that repeats: "Master, Master, what is the secret, what is the silence?" They reach the edge of a cliff. A tree is overlooking the empty almost at horizontal. The old monk commanded his young friend: «Walk on balance along this branch." The young monk cautiously advances above empty. "Now, the patriarch said, stop, get down, bite quickly the branch between your teeth and hang up in the wind like the green fruit that you are!" The young monk, very nervous but much disciplined obeys his master, and soon he is hanging above the empty, held only by its own jaws. "Now, said the master, tell me, what is the secret, what the silence?