Infinity symbol in bookbinding to indicate that a book is printed on acid-free paper and will therefore be long-lasting. In modern mysticism, the infinity symbol has become identified with a variation of the ouroboros, an ancient image of a snake eating its own tail that has also come to symbolize the infinite, and the ouroboros is sometimes drawn in figure-eight form to reflect this identification, rather than in its more traditional circular form. In the works of Vladimir Nabokov, including "The Gift" and "Pale Fire", the figure-eight shape is used symbolically to refer to the Möbius strip and the infinite, for instance
Infinity and the Mind the author's personal contact with Kurt Gödel. An appendix contains one of the few popular expositions on set theory research on what are known as "strong axioms of infinity." "Infinity and the Mind" was reviewed by the "New Yorker", which asserted that "Rudy Rucker's "Infinity and the Mind" is a terrific study with real mathematical depth." Martin Gardner described the book as "Informal, amusing, witty, profound... In an extraordinary burst of creative energy, Rudy Rucker has managed to bring together every aspect of mathematical infinity... A dizzying glimpse into that boundless region of blinding light where the mysteries of transcendence