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 BBC Micro. The Master's slots replace the READY signal with an R/W signal so that RAM can also be plugged into the external cartridge ports. Acorn MOS supports up to 16 Sideways banks. Due to limited motherboard space, extra Sideways sockets were made available by third-party expansion boards. Certain boards, such as the Watford Electronics Sidewise board, also provided the option of permanent, battery backed-up RAM. This allows for developer testing of new Sideways ROM software without burning an EPROM for each attempt. A write-protect switch could be used to prevent the contents of Sideways RAM from being modified. Sideways