Triple-shell symmetry inα-(Al,Si)-Mn

Abstract
We describe three-dimensional graphics modeling experiments executed on a calligraphic system. Utilizing precise data from neutron diffraction, a triple icosahedral shell has been identified in the α-(Al,Si)-Mn phase. These triple shells are centered in the unit cell; the Pm3¯ structure is completed by double shells on the cube corners. The triple shell can also be viewed as a composite of twelve coordination icosahedra around the maganese sites on the second (MacKay) shell.