Watermelon Story

There was a farmer who grew watermelons. He was doing pretty
well, but he was disturbed by some local kids who would sneak into
his watermelon patch at night and eat his watermelons. After some
careful thought, he came up with a clever idea that he thought
would scare the kids away for sure.

He made up a sign and posted it in the field. The next day, the
kids show up and they saw the sign which read: "Warning! One
of the watermelons in this field has been injected with cyanide." The kids ran off, made up their own sign and posted it next to
the farmer's sign. When the farmer returned, he surveyed the field.

He noticed that no watermelons are missing, but the sign next to
his read: "Now there are two!"