Life
====

     Life is a game in which the rules require no observer input. It plays by
itself. It models living processes and environmental effects on living
things. If an entity is too crowded or too lonely, it will die. If it's
comfortable it will survive, and if conditions are just right, new life will
be born.

     This is modelled by square "cells". These are arranged together like the
squares on a piece of graph paper. Each cell has eight neighbours, four which
share edges and four which share corners, like this:

                      NNN
                      NCN   (C = cell N = a neighbour)
                      NNN

     If a cell has two living neighbours, it will be unchanged.
     If a cell has three living neighbours, it will be alive.
     If a cell has any other number of living neighbours, it will be dead.

     Life is played by assigning life to some cells.  Red and black checkers
may be used on a checkerboard, treating the different colored squares on the
board as being indistinguishable.  Put the black checkers where you want the
cells to be alive.  Then, go across every cell, one at a time, and decide
whether it will be alive or dead.  Put a red checker on a square if that cell
will be alive.  Do not take away any black checker and consider only the black
checkers to make the decision until you are done. When you are done, clean
off the board and replace only the new living cells with black checkers.
These will show the new life generation. Repeat these instructions for the next
generation.

     Some patterns are shown below:

Generation         "Glider"        "Block"        "Blinker"        "R-Pentomino"

                     *               **             ***                 **
    0                *C*             **                                **
                     **                                                 *

                      *              **              *
    1               **C              **              *                  ?
                     **                              *

                      *
    2                * C              etc            etc
                     ***

                     * *
    3                **
                      *

                     * C
    4                * *
                     **

     The glider moves relative to the cell, C. In step 3, C is occupied by the
     upper right cell.
