CREATOR (16K ZX81)
by Simon Lane
from Popular Computing Weekly (15 July 1982) pages 8-9

The secret of immortality has eluded mankind down the ages. Kings and
commoners alike have failed to escape the swathe of the grim reaper. Three
score years and ten has remained the allotted span of a man's life. However ,
a few, a very few, seem to have defied death's relentless march, Tales of
Methuselah, the Fountain of Youth and the Elixir of Life, indicate that
immortality is possible.

As a genetic engineer, you are attempting to discover the secret of
immortality. Working with living cells, you are trying to create a cell
structure that is both stable and constantly rejuvenating. Unfortunately,
there are millions of possible cell combinations and no guarantee that any of
them will lead to immortality.

To help you in your task, a computer simulation of human cells has been
constructed, you must create your own cell structures and watch them develop
over the generations to see if you have succeeded in your quest.


MACHINE CODE

This is a machine code program for the 16K ZX81. It is based on the game of
Life developed by Cambridge mathematician John Horton Conway.

The rules of the game are quite simple. Each cell on the screen has a maximum
of eight possible neighbouring cells. Every cell that is adjacent to either
two or three other cells will survive to the next generation. Any cell with
less than two neighbours will die from isolation while any cell with four or
more neighbours will die from overcrowding.

Each empty cell that is adjacent to three living cells will become a new
living cell in the next generation.

When run, a grey border will appear round the screen with a small cross in
the centre. You must move the cross around the screen, using keys 5, 6, 7 and
8 to create your own cell structure.

Each time you move the cross, press 1 to create a living cell. If you make a
mistake, press 0 to remove it.

When the initial cell structure is complete, type in R. Next, to see how the
structure fares over succeeding generations, press any key apart from the
Space key. When the structure ceases to evolve, press Space and the program
will break.

Lines 100 to 146 contain the machine code in hexadecimal. Lines 150 to 510
Poke the machine code into memory and line 1000 puts the computer into Fast
mode.
