There was a farmer who grew watermelons. He was doing pretty well, but he was plagued by local children who would sneak into his batch at night and steal his watermelons. After some carful thought he come up with a clever idea that he thinks will scare the kids away for sure. So he makes up a sign and sticks it on the field. The sign says "Warning, one of the watermelons in this field has been poisoned." The farmer goes to inspect his field the next morning and finds a new sign that says: "Warning, now two of the watermelons in this field have been poisoned. The farmer never ate from the Watermelon field again.