Right, there's a mad man with a shotgun with 4 hostages in the desert. He buries them up tho their necks in sand (in a row) so they can only see all the people in front of them (ie. 1 sees no one, 2 sees 1, 3 sees 2 and 1 etc.)
He then puts a wall in between 1 and 2 so NO ONE can see 1.
He then puts either a blue or red had on each of their heads (like in the diagram). They do not know what colour hat they are wearing, only the colours of hats the people they can see are wearing.
He then says "There are four hats, two red and two blue. None of you can see the colour of your own hat, but you have one minute without talking for one of you to work out what colour hat you are wearing or I'll kill you all"
After a while one of them says "I know what colour hat I am wearing," He is right.
Who and how?
For Fathers and Sons who enjoy wholy spirits.