The Immortal smiled and stretched, it had been a long, difficult lesson. The student had tried very hard. In fact, when the lesson was over, he had lain his head on the Go board and fallen asleep. It was good to have students that put forth so much effort in their lessons.
As he mused, he became aware of a scurrying noise. Looking about, he saw a cockroach on the floor.
"Another one!" he thought, "The walls hide too many vermin!"
He took up his swatter and moved to take care of the roach. As he did so, a rat, that fancied itself a Go player and had been listening to the lesson, scurried from the wall to the board. It was nearsighted, and stood on its hind legs to see if anything of the postion from the lesson was still on the board.
Smack! The rat heard the swatter fall. It took one last look at the Go board, and when the Immortal cried "Aha!", the rat squealed in fear and ran for the wall...