Features related to the discretization of problems characterized by simple
periodic tilings using cells of various shapes are discussed. Various cell
geometries that tile the plane periodically are considered. Equivalent prob
lems are identified, where the discretization can take place on a parallelo
gram, regardless of the shape of the original cell. These equivalent proble
ms also suggest a numbering of the equations that results in matrices with
interesting and useful properties. Copyright (C) 2001 John Wiley & Sons, Lt
d.