QUASI2D: a program written to demonstrate quasiperiodicity and phason fluctuation

A program is described that demonstrates in two dimensions the concepts of quasiperiodic tiling and phason fluctuations. Tiling patterns having perfect fivefold or eightfold quasiperiodicity are displayed on the computer screen at any one of three chosen scales. These patterns are then progressively altered in real time by the application of phason flips to obtain disordered tiling patterns. Energy parameters may be specified to allow preference for different tile-pair combinations in the resulting distributions. In this way, with different combinations of the energies, distributions varying from pure random tiling to ones in which more ordered microdomains are to be seen may be obtained in real time via Monte Carlo simulation.