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       grav - draws a simple orbital simulation


       grav  [-display  host:display.screen]  [-foreground color] [-background
       color] [-window] [-root] [-mono] [-install] [-visual visual]  [-ncolors
       integer]  [-delay  microseconds]  [-count integer] [-decay] [-no-decay]
       [-trail] [-no-trail]


       The grav program draws a simple orbital simulation


       grav 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 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

       -ncolors integer
               How many colors should be used  (if  possible).   Default  200.
               The colors are chosen randomly.

       -count integer
               Default 12.


               Whether orbits should decay.


               Whether  the  objects should leave trails behind them (makes it
               look vaguely like a cloud-chamber.


       DISPLAY to get the default host and display number.

               to get the name of a resource file that  overrides  the  global
               resources stored in the RESOURCE_MANAGER property.


       X(1), xscreensaver(1), xlock(1)


       Copyright © 1993 by Greg Bowering.

       Permission  to  use, copy, modify, and distribute this software and its
       documentation for any  purpose  and  without  fee  is  hereby  granted,
       provided  that the above copyright notice appear in all copies and that
       both that  copyright  notice  and  this  permission  notice  appear  in
       supporting documentation.


       Greg Bowering <>, 1993.

       Ability  to run standalone or with xscreensaver added by Jamie Zawinski
       <>, 10-May-97.