I have taken a group of students on a school trip. I want to organise them into two groups and so I have given each one a coloured hat. Some hats are red, while others are blue. Each child can see everyone else’s hats, but not their own.
I am feeling obtuse, so I have asked the students to get themselves into two groups based on the colours of their hats, with all the red hats together and all the blue hats together. But! I have told them they are not allowed to talk or communicate in any way.
What strategy should they use to form the two groups?