The teacher handed out blank sheets of paper and told the students to draw whatever they wanted.
Some kids drew a horsey, some drew a rainbow, others drew cats and tigers and cars.
But she noticed one boy was only sitting there, drawing nothing.*
She asked, "Why haven't you drawn anything?"
He answered, "I have drawn what I want."
She reached into her desk drawer and handed him his diploma. He stood and left the room.
When other students noticed his absence, they asked where had gone.
"Will he be back soon?"
"Oh, of course," answered the teacher, "he is bound to come back again."
(The non-metaphysical version of this story is actually a joke, wherein the child's "nothing" is "a cow and some grass"… the cows having eaten all the grass and then, of course, moved on to a different pasture off the page.)