Best X11 Graphics: <david+@cs.cmu.edu>   David Applegate 		   <guy@ulysses.att.com> Guy Jacobson	David Applegate			Guy Jacobson	School of Computer Science	AT&T Bell Laboratories	Carnegie Mellon University	600 Mountain Avenue	Pittsburgh PA 15213		Murray Hill NJ 07974	USA				USAJudges' comments:    Make and run as follows:	make davidguy	davidguy ip_address:server.screen    where 'ip_address' in an IP address of an X server.  For example, try:	davidguy 127.0.0.1:0.0    Of course, may need to supply a more reasonable address.  :-)    Also try:	cp davidguy guydavid	guydavid 127.0.0.1:0.0    Can you determine why this makes a difference.    We permitted this type of entry to win because:	- it did not require X to be on the host system	- both BSD and SVR4 have sockets        Now that X11 and sockets have become 'standard', we plan to open    up the contest to programs that use them.  Future rules will    explain this further.    We are pleased that this entry has helped bring new 'life' into    the contest.    NOTE: The orignal program that won may be found in davidguy.orig.c.	  The author supplied a second version of the program, which	  we have placed in the default location davidguy.c. Selected notes from the authors:    The program is a fully-functional X client.  It talks directly to    the X server through a socket without using Xlib, Xt or any other    wussie toolkit junk.  With no arguments, it will try to run    locally using the unix-domain socket (only on BSD :-( ) or you can    give it a command line argument identifying a display host address    (in dotted octet notation, like 127.0.0.1:0.0) where the X server    is running.  It handles color and monochrome displays, and    performs whatever byte-swapping and bit-reversal is needed (so    that the program works even when the server and the client have    different architectures).  It buffers communication to the X    server for efficiency.    [[ NOTE: The original source in davidguy.c used only an IP address	     argument (assumed :0.0) and assumed the color of black	     and white. ]]    The program doesn't require any user interaction; you can just sit    back and watch it run.  All the action takes place in the root    window of the display.    We think the program is interesting for these reasons:	1) It belongs to a class of programs that programmers make 	   the following complaints about:  they require a mountain 	   of code to implement even the simplest program; and they 	   must be linked with giant libraries of hard-to-understand 	   functions.  In contrast to these complaints (made by wimps,	   in our humble opinion), our program fits in under 1536 	   bytes, doesn't need any external functions except for a few 	   system calls, and doesn't need to include any header files.	2) It implements an extremely efficient algorithm for the 	   computation it performs.  One cool feature of the algorithm 	   (at least as far as this contest is concerned) is that its 	   obscurity is fundamentally necessary for its efficiency.  	   In other words, even if we took steps to present the algorithm 	   clearly, (we haven't) the relation of the computation performed 	   to the specification of what the program was supposed to do 	   would still be hard to understand.    Quasi-spoiler on internals:    The program plays Conway's game of Life in the root window's    background pixmap.  It starts by setting the background to random    bits, and then plays Life, with one Life cell for each pixel of the    screen.  In the game of Life, a cell survives to the next round if    2 or 3 of its 8 neighbors are also alive, and a cell is born if    exactly 3 of its neighbors are alive.  Otherwise, a cell dies of    exposure if it has only 0 or 1 neighbors, and dies of overcrowding    if it has 4 or more neighbors.    The algorithm used to compute the next generation is based on the    observation that a cell's state in the next generation is a boolean    function of its current state, and the states of its 8 neighbors    (ie, a boolean function from 9 bits to 1 bit).  This function can    be computed by a boolean circuit.  In addition, intermediate values    computed by the circuit can be shared between neighboring cells,    reducing the number of gates per cell required.  These ideas    have been used before, to compute the next generation through a    series of bit blits.  Instead of doing this, we map values in the    circuit to bits in registers, so that the next generation can be    computed efficiently within registers, minimizing memory accesses.    As a result, the computation of the next generation is performed    with about 1.6 instructions per life cell, consisting of .125    memory accesses, .17 shifts, and 1.3 logic operations.  The net    result is that the time to transfer the bits to the X server, and    for the X server to draw them on the screen, dominates the time to    compute the next generation.