XScreenSaver(1)

NAME
munch - munching squares

SYNOPSIS
munch [-display host:display.screen] [-foreground color] [-background color] [-window] [-root] [-mono] [-install] [-visual visual] [-delay usecs] [-xor] [-noxor] [-clear number] [-simul number] [-classic | -mismunch | -random] [-fps]

DESCRIPTION
The munch program performs the munching squares hack. It picks square size, position, and gravity randomly. It also displays a creatively broken misimplementation of the classic algorithm. The munching squares hack consists 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 usecs
    The delay between steps of the animation, in microseconds. Default: 2500.

-xor
    Use the XOR drawing function. This is the default.

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

-clear number
    Number of squares to misdraw before clearing the display. Default: 65.

-simul number
    Number of squares to misdraw simultaneously. Default: 5.

-classic
    Draw classic munching squares only.

-mismunch
    Draw "mismunch" only.

-random
    Do one or the other.

-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.

SEE ALSO
X(1), xscreensaver(1),
    http://www.inwap.com/pdp10/hbaker/hakmem/hakmem.html

HISTORY
HAKMEM: MIT AI Memo 239, Feb. 29, 1972.
    Beeler, M., Gosper, R.W., and Schroeppel, R. "Unless otherwise stated, all computer programs are in PDP-6/10 assembly 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 1997 Tim Showalter.
    Copyright 2004 Steven Hazel.
        Copyright 1992-2008 Jamie Zawinski.

        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.