XScreenSaver(1) 					      General Commands Manual						   XScreenSaver(1)

NAME

       munch - munching squares screen hack

SYNOPSIS

       munch  [-display host:display.screen] [-foreground color] [-background color] [-window] [-root] [-mono] [-install] [-visual visual] [-delay
       seconds] [-xor] [-noxor] [-shift] [-noshift] [-logminwidth minimum width]

DESCRIPTION

       The munch program preforms the munching squares hack until killed.  It picks square size,  position,  and  gravity  randomly;  configurable
       options are listed below.

       The  munching squares hack cosists of drawing Y = X XOR T for a range of X and T over and over until all the possible combinations of X and
       T have come up.	It was reportedly discovered by Jackson Wright in 1962 and took 5 instructions of PDP-6 code.

OPTIONS

       munch 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.

       -delay seconds
	       How long to wait before starting over.  Default 5 seconds.

       -xor    Use the XOR drawing function.  (Default.)

       -no-xor Don't use the XOR drawing function.

       -shift  Start drawing the square at weird starting points.  (Default.)

       -no-shift
	       Don't shift and start drawing the square at weird starting points.

       -logminwidth minimum-width
	       The logarithm (base 2) of the minimum with of a square (must be a power of 2, or some parts of the square aren't.)

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.

SEE ALSO

       X(1), xscreensaver(1), http://www.inwap.com/pdp10/hbaker/hakmem/hakmem.html, http://www.comedia.com/Hot/jargon_3.0/JARGON_M/MUNCHSQR.HTML

HISTORY

       Quoted from HAKMEM, for historical interest.  As that document says, "Unless otherwise stated, all computer programs are in PDP-6/10 assem-
       bly language."

       ITEM 146: MUNCHING SQUARES
	       Another simple display program. It is thought that this was discovered by Jackson Wright on the RLE PDP-1 circa 1962.

		   DATAI 2
		   ADDB 1,2
		   ROTC 2,-22
		   XOR 1,2
		   JRST .-4
	       2=X, 3=Y. Try things like 1001002 in data switches. This also does interesting things with operations other than XOR, and rotations
	       other than -22. (Try IOR; AND; TSC; FADR; FDV(!); ROT -14, -9, -20, ...)

       ITEM 147 (Schroeppel):
	       Munching squares is just views of the graph Y = X XOR T for consecutive values of T = time.

       ITEM 148 (Cohen, Beeler):
	       A modification to munching squares which reveals them in frozen states through opening and closing curtains: insert FADR 2,1 before
	       the XOR. Try data switches =

		   4000,,4    1000,,2002    2000,,4    0,,1002
	       (Notation: <left half>,,<right half>)

	       Also try the FADR after the XOR, switches = 1001,,1.

COPYRIGHT

       Copyright  (C)  1997  by  Tim Showalter.  Permission to use, copy, modify, distribute, and sell this software and its documentation for any
       purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both  that  copyright  notice
       and  this permission notice appear in supporting documentation.	No representations are made about the suitability of this software for any
       purpose.  It is provided "as is" without express or implied warranty.

AUTHOR

       Tim Showalter <tjs@andrew.cmu.edu>, 17-Jun-97, based on what's in the Jargon File and stealing stuff from existing xscreensaver modules.

X Version 11							     17-Jun-97							   XScreenSaver(1)