Medieval Quasicrystals

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In designing architectural structures, medieval Islamic artisans hit on so-called quasicrystals, a complex pattern made famous by renowned mathematician Roger Penrose in the 1970s. After seeing hints of the pattern while traveling in Uzbekistan, Peter J. Lu, a physics graduate student at Harvard University, pored over photographs from Iran, Iraq, Turkey and Afghanistan. Some of the ornate tile work, called girih, could have only been accurately constructed using a set of five tiles—a bow tie, pentagon, diamond, elongated hexagon and large decagon—conclude Lu and co-author Paul J. Steinhardt of Princeton University. The tiling practice reached great sophistication with the Darb-i Imam shrine in Iran, which dates to 1453; it displays a symmetric pattern of pentagons and 10-sided stars. If extended indefinitely in all directions, this pattern would never repeat itself—the hallmark of a quasicrystal. The researchers describe their conclusions in the February 23 Science.

Scientific American Magazine Vol 296 Issue 5This article was published with the title “Medieval Quasicrystals” in Scientific American Magazine Vol. 296 No. 5 (), p. 36
doi:10.1038/scientificamerican0507-36c

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