Subject: 08/95 Quasicrystal 1.JPG Author: W. Stuart Edwards and Stephan Fauve Uploaded By: CHansen598 Date: 7/7/1995 File: SciCit02.JPG (51497 bytes) Estimated Download Time (53797 baud): < 1 minute Download Count: 236 Needs: JPEG Viewer From the August 1995 issue of SCIENTIFIC AMERICAN Science and the Citizen Quasimodal by Madhusree Mukerjee This 516 x 480 pixel image shows that quasicrystals, discovered in 1984, shattered the wisdom that shapes having fivefold, sevenfold or other designated symmetries cannot fit together to tile a surface. Now the forbidden quasipatterns can also be seen simply by shaking a shallow layer of gooey liquid up and down. In 1831 Michael Faraday had observed that such vertical vibrations create arrays of standing waves on the surface. W. Stuart Edwards of Haverford College in Pennsylvania and Stephan Fauve of the Ecole Normale Superieure in Lyon, France, find that vibrating a platter of dilute glycerol--that is 85 times as viscous as water--with two simultaneous frequencies may generate quasipatterns of 12-fold symmetry. When combined with diverse amplitudes and phases, the oscillations give rise to a variety of designs, including double spirals and six-sided honeycombs. The patterns and their defects bring to light subtle interactions between the fluid's molecules