more from Tanya:
Once upon a time there was a land where the only antidote to a poison was a stronger poison. In this land, a dragon challenges a king to a duel and the king accepts. The rules of the duel are as follows: Each dueler has a cup of poison. First, they exchange cups. Then, each dueler drinks half of the poison in front of them. After that, they exchange again and drink their own poisons. The survivor wins. The king knows that the dragon will use a stronger poison than any the king will ever make.
How can the king win the duel?