Welcome to Poisonland, a world just like ours but with one very strange rule; drinking any poison will kill you unless you drink an even stronger poison soon after.
The Ruler of Poisonland wakes up one day and decrees that they must have the strongest poison that exists. So they call for the two highest ranking council members; the Master of Potions and the Minister of Network Security (they're very protective of their digital data in Poisonland). The Ruler says “You both have ten days to make for me the strongest poison feasible. You will each enter my chamber, drink some of the others poison and then drink your own. Whoever makes the strongest poison shall live and I will have the strongest poison in the land!”
The Minister of Network Security leaves, wringing their hands in despair. There was no way they'd be able to make a stronger poison than the Master of Potions. But a thought strikes them! They come up with a way of following the rules of the contest and live without having to make a stronger poison than the Master of Potions. They set about their plan.
A few days later, the Master of Potions hears about this plan. “That cunning devil!” they proclaim, and sets a new plan of their own into motion.
Once the ten days is over, the two council members enter the Rulers chamber, drink from the others bottle and then from their own. A moment later, the Minister of Network Security drops dead.
Now the questions:
What was the Minister of Network Security's plan?
How did the Master of Potions get around the plan?
Did the Ruler get the strongest poison in the land?
The answers:
The Minister of Network Security made a mild poison, which they drank before entering the Ruler's chambers, but brought in with them a bottle of water. They would drink the strong poison from the Master of Potions next (followed by some water), which would counter the mild poisons effect.
The Master of Potions also brought in a bottle of water, meaning the mild poison they consumed before entering the chamber would kill the Minister of Network Security.
The Ruler got nothing more than a bottle of water.