In reply to @sapinker

Steven Pinker

@sapinker · Twitter ·

Here are the puzzles: variants of "When is Cheryl's Birthday," the "Spinach-in-Teeth/Muddy Children/Unfaithful Husbands" problem, and (an easy one) "Three Logicians Walk Into a Bar," explained in When Everyone Knows That Everyone Knows...: Common Knowledge and the Mysteries of