The teacher said “What is this?”
Little Johnny replied “It’s a drawing of a cow eating grass”
The teacher looked at the piece of paper and said to Johnny “Where’s the grass?”
Little Johnny replied “The cow ate all of it”
The teacher looked at the paper again, and asked him “then, where’s the cow?”
Without hesitation, Little Johnny replied, “It left because there was no more grass”.
Image used under a Collective Commons License from https://pixabay.com/photos/paper-blank-white-empty-page-2221812/