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
Diple (textual symbol) to draw attention to separate concepts and "diple periestigmene" used (like obelos) to mark dubious passages. "Diple obolismene" was used according to Isidore to separate sentences in comedies and tragedies, so its usage was similar to that of paragraphos. Diple (textual symbol) Diple (, meaning double, referring to the two lines in the mark >) was used in margins to draw attention to something in text. It is sometimes also called antilambda because the sign resembles a Greek capital letter lambda (Λ) turned upon its side. In some ways its usage was similar to modern day quotation marks; guillemets («