Glass patterns in the superposition of aperiodic line gratings

Abstract

In the previous chapters we saw that when two identical aperiodic dot screens are superposed on top of each other with a small angle or scaling difference, or with any other slight transformation, a typical Glass pattern appears in the superposition (see, for example, Figs. 2.1(c), (e) and (g)). Unlike moiré effects between periodic layers, which extend throughout the entire superposition (see, for example, Fig. 2.1(d), (f) and (h)), Glass patterns are concentrated about the fixed points of the transformation, and farther away they gradually fade out and disappear.