SIMPLE SOLUTIONS

# PENROSE(6X) - Linux man page online | Games

Draws quasiperiodic tilings.

Chapter
5.36 (10-Oct-2016)
penrose(6x) XScreenSaver manual penrose(6x)

## NAME

penrose - draws quasiperiodic tilings

## SYNOPSIS

penrose [-display host:display.screen] [-foreground color] [-background color] [-window] [-root] [-mono] [-install] [-visual visual] [-ncolors integer] [-delay microseconds] [-size integer] [-ammann] [-no-ammann] [-fps]

## DESCRIPTION

The penrose program draws quasiperiodic tilings. See Onoda, Steinhardt, DiVincenzo and Socolar in Phys. Rev. Lett. 60, #25, 1988 or Strand‐ burg in Computers in Physics, Sep/Oct 1991. This implementation uses the simpler version of the growth algorithm, i.e., if there are no forced vertices, a randomly chosen tile is added to a randomly chosen vertex (no pref‐ erence for those 108 degree angles). There are two essential differences to the algorithm presented in the literature: First, we do not allow the tiling to enclose an untiled area. Whenever this is in danger of hap‐ pening, we just do not add the tile, hoping for a better random choice the next time. Second, when choosing a vertex randomly, we will take one that lies withing the viewport if available. If this seems to cause enclosures in the forced rule case, we will allow invisible vertices to be chosen. Tiling is restarted whenever one of the following happens: there are no incomplete ver‐ tices within the viewport or the tiling has extended a window's length beyond the edge of the window horizontally or vertically or forced rule choice has failed 100 times due to areas about to become enclosed. Although quasiperiodic tilings are produced, the tiles themselves are not penrose tiles (darts and kites). In contrast to penrose tiles, these tiles can be arranged to form a periodic tiling.

## OPTIONS

penrose accepts the following options: -window Draw on a newly-created window. This is the default. -root Draw on the root window. -mono If on a color display, pretend we're on a monochrome display. -install Install a private colormap for the window. -visual visual Specify which visual to use. Legal values are the name of a visual class, or the id number (decimal or hex) of a specific visual. -ncolors integer How many colors should be used (if possible). Default 64. The colors are chosen randomly. -size integer How big the tiles should be. Default 40 pixels. -delay milliseconds How long (in 1/1,000,000'ths of a second) to wait between drawing each tile. Default 10,000 or .01 seconds. -ammann -no-ammann Whether Ammann lines should be added. -fps Display the current frame rate and CPU load.

## ENVIRONMENT

DISPLAY to get the default host and display number. XENVIRONMENT to get the name of a resource file that overrides the global resources stored in the RESOURCE_MANAGER property.