A friend from my college days named Mike Frank made the hand-drawn puzzle below. The object is to determine which picture breaks the pattern. Below the hand-drawn image is a more abstract version of the same idea.
No one has figured it out yet. Everyone agrees, once the answer is explained, that it is correct and very clever.
Questions/comments to Heron Stone.
Truth-tellers always tell the truth.
Liars always lie.
You come to a fork in the road.
There are two people standing there and from their dress
you determine that one is a Truth-teller and the other is a Liar.
But you don't know which is which.
You turn to one of them and ask, "Are you a Truth-teller or a Liar?"
The person answers, but he mumbles and you don't understand what he said.
So you turn to the other man and ask, "What did he say?"
The seconds man says, "He said he's a liar."
How do you know?