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
Sideways address space methods are: removing chips from the board and placing them into an expansion board that occupies the chips' original sockets, and: fitting a RAM module in a ROM socket with a flying lead connected to a write signal elsewhere on the motherboard. The 64kB model B+ had 12kB of "special" sideways ram. This used the sideways address but was selected by the high bit of the rom select register and could not be used to load rom images. The 128kB model B+ had an expansion board with 64kB of "regular" sideways ram in addition to the 12kB of "special" sideways