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From: bombadil@diku.dk (Kristian Nielsen)
Newsgroups: comp.graphics
Subject: Re: 3D Life
Message-ID: <1991Mar22.153730.2229@odin.diku.dk>
Date: 22 Mar 91 15:37:30 GMT
References: <1991Mar15.151712.23199@ux1.cso.uiuc.edu>
Sender: news@odin.diku.dk (Netnews System)
Organization: Department of Computer Science, U of Copenhagen
Lines: 52

gsb19079@uxa.cso.uiuc.edu (Gerald Scott Bradley) writes:

>Thanks to those who answered some of my questions before...now here's another:

>Does a 3D version of Life exist, and if so what are the rules and where could
>I get a hold of a copy?

  The rules (as far as I remember them from an old Scientific American, I may
remember wrong, and there may be other ways) are similar to the 2D version,
only the number of neighbours are different. Each cell has 26 neighbours
(since a 3-by-3 cube has 3x3x3=27 'subcubes'). Each version of life (The
article in Scientific American discussed at least two) is expressed as a
string of 4 numbers xyzw, where x and y are the minimum/maximum number of
neighbours that a cell can have to survive, while z and w are the min/max
for an empty(dead) cell to be reborn. So, the original life can be expressed
as 2333 - a cell with 2 or 3 neighbours survives, and an empty cell with 3
neighbours is born anew.
  The article mainly discussed the 5766 version (and I think also the 4555
version, though I'm not quite sure about that one). One interesting point
about 5766 is that it can be brought to simulate the original 2D-life(so
that it can be regarded as a kind of 'generalisation' over the 2D-version).
It is VERY difficult to show in ASCII, but it involves creating two planes
like this:
     __________________
    /  /  /  /  /  /  /[
    [ ][ ][ ][ ][ ][ ]/[
    [ ][#][ ][ ][#][ ]/[
    [ ][ ][ ][ ][ ][ ]/[
    [ ][ ][ ][ ][ ][ ]/[
    [ ][#][ ][ ][#][ ]/[
    [ ][ ][ ][ ][ ][ ]/

Now, place two of these planes at a distance of 4 cells apart, and place two
identical layers in the middle containing the pattern desired for the
2D-life. This way, these layers in the middle will evolve exactly like the
2D-life.
  If anyone shows any further interest in this, I guess I could figure out
the exact number sequence for '4555', and in which issue the article
appeared.

  As to where you could get a copy, you're wellcome to my original version for
my old Sinclair ZX-Spectrum! (If you can give me a clue as to how to get it
from tape on to internet....) In optimised assembler and all....



>			Thanks...
>				Scott

	Hope this isn't too incomprehensible...

	Kristian