Your goal in this game is to get gems.
There are a few simple rules which are always true:
1. At least one box only tells the truth.
2. At least one box only lies.
3. Exactly one box has gems in it. The others are empty.
4. You may open up to two boxes per round.
This game is based on but not affiliated with the Parlor room puzzle from Blue Prince.
You should check out Blue Prince if you find this game interesting.