And for today, a new original hat guessing puzzle!
CHALLENGE: Guess the hats of the 4 prisoners.
SPECIAL RULE: One of the prisoners is lying
DESCRIPTION: Each one can see the hats that are in front of them, and not their own.
They give some tips about what they see (remember one of them is lying):
1- A sees B, C and D, but he says he only sees 1 green hat.
2- B sees C and D, and he assures he sees a green hat on both of them.
3- D, who is looking in the opposite direction, can see A, B and C, and claims to see 2 green hats together.
There are 2 green hats and 2 black hats, so everybody must wear a hat.