Structure of glass: supercomputer graphics showing the results of a simulation of the formation of silicon dioxide (SiO2) glass. The building blocks of this material (units of SiO4) are represented by blue tetrahedra. The computer simulation that produced this image mirrored the actual physical processes that occur in the formation of glass. The entire simulation took 22 hours of processing time on a CRAY XMP supercomputer. The starting point was the known crystal structure for beta crystobalite, which was heated until molten. After some time as a liquid, the system was quenched & the glass freezed out.