1munch(6x) XScreenSaver manual munch(6x)
2
6 munch - munching squares screen hack
7
9 munch [-display host:display.screen] [-foreground color] [-background
10 color] [-window] [-root] [-mono] [-install] [-visual visual] [-delay
11 microseconds] [-xor] [-noxor] [-shift] [-noshift] [-logminwidth minimum
12 width]
13
15 The munch program performs the munching squares hack until killed. It
16 picks square size, position, and gravity randomly; configurable options
17 are listed below.
18 The munching squares hack consists of drawing Y = X XOR T for a range
20 of X and T over and over until all the possible combinations of X and T
21 have come up. It was reportedly discovered by Jackson Wright in 1962
22 and took 5 instructions of PDP-6 code.
23
25 munch accepts the following options:
26 -window Draw on a newly-created window. This is the default.
28 -root Draw on the root window.
30 -mono If on a color display, pretend we're on a monochrome display.
32 -install
34 Install a private colormap for the window.
35 -visual visual
37 Specify which visual to use. Legal values are the name of a
38 visual class, or the id number (decimal or hex) of a specific
39 visual.
40 -delay microseconds
42 How long to wait before starting over. Default 5000.
43 -xor Use the XOR drawing function. (Default.)
45 -no-xor Don't use the XOR drawing function.
47 -shift Start drawing the square at weird starting points. (Default.)
49 -no-shift
51 Don't shift and start drawing the square at weird starting
52 points.
53 -logminwidth minimum-width
55 The logarithm (base 2) of the minimum with of a square (must be
56 a power of 2, or some parts of the square aren't.)
57
59 DISPLAY to get the default host and display number.
60 XENVIRONMENT
62 to get the name of a resource file that overrides the global
63 resources stored in the RESOURCE_MANAGER property.
64
66 X(1), xscreensaver(1), http://www.inwap.com/pdp10/hbaker/hakmem/hak‐
67 mem.html, http://www.comedia.com/Hot/jargon_3.0/JARGON_M/MUNCHSQR.HTML
68
70 Quoted from HAKMEM, for historical interest. As that document says,
71 "Unless otherwise stated, all computer programs are in PDP-6/10 assem‐
72 bly language."
73 ITEM 146: MUNCHING SQUARES
75 Another simple display program. It is thought that this was
76 discovered by Jackson Wright on the RLE PDP-1 circa 1962.
77 DATAI 2
79 ADDB 1,2
80 ROTC 2,-22
81 XOR 1,2
82 JRST .-4
83 2=X, 3=Y. Try things like 1001002 in data switches. This also
84 does interesting things with operations other than XOR, and
85 rotations other than -22. (Try IOR; AND; TSC; FADR; FDV(!); ROT
86 -14, -9, -20, ...)
87 ITEM 147 (Schroeppel):
89 Munching squares is just views of the graph Y = X XOR T for
90 consecutive values of T = time.
91 ITEM 148 (Cohen, Beeler):
93 A modification to munching squares which reveals them in frozen
94 states through opening and closing curtains: insert FADR 2,1
95 before the XOR. Try data switches =
96 4000,,4 1000,,2002 2000,,4 0,,1002
98 (Notation: <left half>,,<right half>)
99 Also try the FADR after the XOR, switches = 1001,,1.
101
103 Copyright © 1997 by Tim Showalter. Permission to use, copy, modify,
104 distribute, and sell this software and its documentation for any pur‐
105 pose is hereby granted without fee, provided that the above copyright
106 notice appear in all copies and that both that copyright notice and
107 this permission notice appear in supporting documentation. No repre‐
108 sentations are made about the suitability of this software for any pur‐
109 pose. It is provided "as is" without express or implied warranty.
110
112 Tim Showalter <tjs@andrew.cmu.edu>, 17-Jun-97, based on what's in the
113 Jargon File and stealing stuff from existing xscreensaver modules.
114X Version 11 5.05-3 (06-Apr-2008) munch(6x)