The lemniscate resembles a Moebius loop, also called a Moebius strip (named for the 19th-century mathematician August Ferdinand Möbius). The Möbius loop is a slightly twisted, two-dimensional surface. It can be easily reproduced by twisting a long paper strip by 180° and sticking its ends together. Though made of double-sided paper, a Möbius loop characteristically has only one side, as you can easily see by drawing a continuous line on it. ►Escher often made use of Möbius loops in his graphic approaches to infinity:
If you're looking for the lemniscate on your PC keyboard, you'll find it under character no. 221E in Unicode fonts. You can copy it into any text with the Windows system program charmap.
* The lemniscate equation is (x2 + y2)2 - 2a2(x2 - y2) = 0.
** All rights for Escher graphics are with M.C. Escher Company B.V., http://www.mcescher.com