In an experiment on the parametric excitation of capillary waves (the Faraday instability) we have observed a stable standing-wave pattern with twelvefold orientational order. This ‘‘quasipattern’’ is analogous to a two-dimensional quasicrystal, but it occurs in a macroscopic nonequilibrium fluid-dynamical system. It is observed in containers whose side walls are of various shapes including an irregular shape, and thus it cannot be ascribed to side-wall boundary effects.

• Received 15 June 1992

DOI:https://doi.org/10.1103/PhysRevE.47.R788