# Recursive Book Cover Is Recursive

The cover art for Paul Halmos' book on Naive Set Theory plays with the self-referential nature of Russel's Paradox, to humorous visual effect.

The cover art for Paul Halmos' book on Naive Set Theory plays with the self-referential nature of Russel's Paradox, to humorous visual effect.

How's your Monday coming along? Pretty rough? Well it's about to get a little hairier. If I'm not mistaken, this self-referential brain teaser is a play on the age-old Liar's paradox, (or, for those of you familiar with set theory, Russell's paradox), reframed in the form of a multiple-choice question.