By studying the periodic drawings of the Dutch Artist M.C. Escher, we
find that the simplest group of the seventeen wallpaper group, P1, can
be 'visualized' in the upper halfplane as a symmetrical tessellation
with self-similar properties. Iterative mappings are constructed and a
n algorithm is presented to automatically generate coloured patterns w
ith this symmetry. This method can be used to create a great variety o
f artistic symmetrical patterns. (C) 1998 Elsevier Science Ltd. All ri
ghts reserved.