Prince Hattius tests his three wisest men with a hat puzzle. He tells them that he’ll put a hat on each of their heads, either green or yellow. These wise men, used to such puzzles, know that in such a setup they’ll be able to see the colours of the other two hats, but not their own.
Then the Prince says that at least one hat is green and the winner is the first person to work out the colour of his own hat. He adds on that this puzzle is fair to all of them - what happens?