 натисни тук за информация на български
Girih pattern from the Seljuk Mama Hatun Mausoleum in Tercan, Turkey
(about AD 1200), with girih-tile reconstruction overlaid at bottom
*
Decagonal quasicrystal geometry, first understood by Westerners in recent decades, appears in 15th-century Islamic tilings...
Intricate decorative tilework found in medieval architecture across
the Islamic world appears to exhibit advanced decagonal quasicrystal
geometry -- a concept discovered by Western mathematicians and
physicists only in the 1970s and 1980s. If so, medieval Islamic
application of this geometry would predate Western mastery by at least
half a millennium.
The finding, by Peter J. Lu at Harvard University and Paul J.
Steinhardt at Princeton University, will be published this week in the
journal Science.
"We can't say for sure what it means," says Lu, a graduate student
in physics at Harvard's Graduate School of Arts and Sciences. "It could
be proof of a major role of mathematics in medieval Islamic art or it
could have been just a way for artisans to construct their art more
easily. It would be incredible if it were all coincidence, though. At
the very least, it shows us a culture that we often don't credit enough
was far more advanced than we ever thought before."
Breathtakingly elaborate geometric tiling is a distinctive feature
of medieval Islamic architecture throughout the Middle East and Central
Asia. Art historians have long assumed that simpler elements of the
patterns were created with elementary tools such as straightedges and
compasses. But there has been no explanation for how artists and
architects could have created the unmistakably complex tile patterns
adorning many medieval Islamic edifices.
"Straightedges and compasses work fine for the recurring symmetries
of the simplest patterns we see," Lu says, "but it probably required
far more powerful tools to fully explain the elaborate tilings with
decagonal symmetry."
While it's possible to create these patterns individually with basic
tools, they are incredibly difficult to replicate on a larger scale
without generating extensive geometric distortions. The most complex
medieval Islamic tilings have little such distortion, leading Lu to
believe more is at play.
"Individually placing and drafting hundreds of decagons with a
straightedge would have been exceedingly cumbersome," Lu says. "It's
much more likely these artisans used particular tiles that we've found
by decomposing the artwork."
These tiles, dubbed "girih tiles" by Lu and Steinhardt, consist of
sets of five contiguous polygons (a decagon, pentagon, diamond, bowtie,
and hexagon), each with a unique decorative line pattern. For medieval
Islamic artisans, they may have represented a toolkit for generating
huge numbers of distinctive tile patterns without the lengthy,
painstaking, and often flawed process of creating each line segment
individually.
These girih tiles may have been used to generate a wide range of
complex tiling patterns on major buildings from medieval Islam,
including mosques in Isfahan, Iran, and Bursa, Turkey; madrasas in
Baghdad; and shrines in Herat, Afghanistan, and Agra, India.
In some cases, Lu found girih tiles used to create patterns of two
distinct scales on medieval Islamic buildings. This approach generates
infinite patterns with decagonal symmetry that never repeats -- also
known as a quasicrystalline tiling, a phenomenon first described in the
West in the 1970s by famed British mathematician Roger Penrose and more
fully explained by Steinhardt and Dov Levine over the past 30 years.
In addition to examples on medieval structures that are still
standing, Lu has been able to match his girih tiles with drawings in
15th-century Persian scrolls drafted by master architects to document
their techniques.
"We're finding widespread evidence for the same approach being used
for 500 years across the Islamic world," Lu says. "Again and again,
girih tiles provide logical explanations for complicated designs."
Lu and Steinhardt's tile study was supported in part by Harvard's Aga Khan Program for Islamic Architecture and by C. and F. Lu.
source
22 February 2007
See also:
|
