1penrose(6x)                   XScreenSaver manual                  penrose(6x)
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NAME

6       penrose - draws quasiperiodic tilings
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SYNOPSIS

9       penrose  [--display  host:display.screen] [--foreground color] [--back‐
10       ground color] [--window] [--root] [--window-id  number][--mono]  [--in‐
11       stall]  [--visual  visual]  [--ncolors  integer] [--delay microseconds]
12       [--size integer] [--ammann] [--no-ammann]
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14       [--fps]
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DESCRIPTION

17       The penrose program draws quasiperiodic tilings.
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19       See Onoda, Steinhardt, DiVincenzo and Socolar in Phys. Rev.  Lett.  60,
20       #25, 1988 or Strandburg in Computers in Physics, Sep/Oct 1991.
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22       This  implementation  uses the simpler version of the growth algorithm,
23       i.e., if there are no forced vertices, a randomly chosen tile is  added
24       to  a  randomly  chosen  vertex (no preference for those 108 degree an‐
25       gles).
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27       There are two essential differences to the algorithm presented  in  the
28       literature:  First,  we  do  not allow the tiling to enclose an untiled
29       area.  Whenever this is in danger of happening, we just do not add  the
30       tile,  hoping  for  a better random choice the next time.  Second, when
31       choosing a vertex randomly, we will take one that lies within the view‐
32       port  if  available.   If  this seems to cause enclosures in the forced
33       rule case, we will allow invisible vertices to be chosen.
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35       Tiling is restarted whenever one of the following happens: there are no
36       incomplete  vertices  within  the viewport or the tiling has extended a
37       window's length beyond the edge of the window  horizontally  or  verti‐
38       cally  or forced rule choice has failed 100 times due to areas about to
39       become enclosed.
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41       Although quasiperiodic tilings are produced, the tiles  themselves  are
42       not  penrose  tiles  (darts  and  kites). In contrast to penrose tiles,
43       these tiles can be arranged to form a periodic tiling.
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45

OPTIONS

47       penrose accepts the following options:
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49       --window
50               Draw on a newly-created window.  This is the default.
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52       --root  Draw on the root window.
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54       --window-id number
55               Draw on the specified window.
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57       --mono  If on a color display, pretend we're on a monochrome display.
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59       --install
60               Install a private colormap for the window.
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62       --visual visual
63               Specify which visual to use.  Legal values are the  name  of  a
64               visual  class,  or the id number (decimal or hex) of a specific
65               visual.
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67       --ncolors integer
68               How many colors should be used (if possible).  Default 64.  The
69               colors are chosen randomly.
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71       --size integer
72               How big the tiles should be.  Default 40 pixels.
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75       --delay milliseconds
76               How long (in 1/1,000,000'ths of a second) to wait between draw‐
77               ing each tile.  Default 10,000 or .01 seconds.
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79
80       --ammann
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82       --no-ammann
83               Whether Ammann lines should be added.
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85
86       --fps   Display the current frame rate and CPU load.
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ENVIRONMENT

89       DISPLAY to get the default host and display number.
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91       XENVIRONMENT
92               to get the name of a resource file that  overrides  the  global
93               resources stored in the RESOURCE_MANAGER property.
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95       XSCREENSAVER_WINDOW
96               The window ID to use with --root.
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SEE ALSO

99       X(1), xscreensaver(1), xlock(1)
100
102       Copyright © 1996 by Timo Korvola.
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104       Permission  to  use, copy, modify, and distribute this software and its
105       documentation for any purpose and without fee is hereby  granted,  pro‐
106       vided  that  the  above  copyright notice appear in all copies and that
107       both that copyright notice and this permission notice  appear  in  sup‐
108       porting documentation.
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AUTHOR

111       Timo Korvola <tkorvola@dopey.hut.fi>, 1996.
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113       Ability  to run standalone or with xscreensaver added by Jamie Zawinski
114       <jwz@jwz.org>, 10-May-97.
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118X Version 11               6.06-1.fc37 (12-Dec-2022)               penrose(6x)
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