Anyone interested in this might get a kick out of the book “To Mock A Mockingbird”.<p>The first half of the book is an almost exhaustive exploration of self-referential riddles. Like “if the barber shaves everyone who doesn’t shave themselves, who shaves the barber?” and “if one gremlin always tells the truth and the other always lies, how can you ask them for directions?”<p>The second half of the book is a rigorous examination of combinatorial logic through an analogy of birds who make calls depending on the calls of other birds they hear. It touches on function composition,recursion, fixed points, godels theorems, and the Y combinator (the mockingbird).<p>My only gripe with the book is that it stays completely within the bird metaphor, and doesn’t always explicitly state the underlying math concept.