Queen Hattius has two prisoners and gives them a puzzle. If they succeed, then she’ll let them free. She will randomly put a hat on each of their heads. The hats could be red or blue. They will simultaneously guess the colour of their own hat, and if at least one person is correct, then they win.
Each prisoner can only see the other prisoner’s hat - and not their own. The prisoners aren’t allowed to communicate once they’re wearing the hats, but they’re allowed to come up with a strategy before.
What should their strategy be?