Usage: Life1D <rows> <rule>
    This program simulates 1D Life: the simplest class of one-dimensional
    cellular automata in a <ROWS=rows+1> x <COLS=2*rows+1> grid starting
    with a single live cell in the middle of the top row using rule <rule>.
    These 1D rules are defined in Wolfram's Elementary Cellular Automata:
    http://mathworld.wolfram.com/ElementaryCellularAutomaton.html
    This program will print to stdout data in plain PBM file format.
    This output can be easily viewed using the display command or 
    converted to a another format using the pbmto* and ppmto* utilities. 
    A plain ascii PBM file can be created by adding a header line 
    "P1 <WIDTH> <HEIGHT>" and followed by a grid of data 
    (0 = dead = white, 1 = live = black). Add a comment on the first 
    line with a brief description of the image.
  Arguments:
    <rows> is a positive integer specifying the number of rows to generate
    (not counting the first "seed row" which is all dead except for a central
    live cell). The columns are computed automatically -- enough so that
    the rule, if it were to grow in the normal triangular pattern, would
    just perfectly reach the edge. Off the board is considerered "dead".
    <rule> is a number from 0-255 specifying the rule to use.