#implement rule 110 cellular automata
$init = "  X  ";  #initial value (pad with two spaces on either side)
$"="";

for (1..24)
{
    print ' ' x (38-$_)."$init\n";
    $init=" @{[($init=~m/^(\s)             | #Start of line
                     (?<=\s)(\s)(?=\s)     | #000
                     (?<=\s) \s (?=(X))    | #001
                     (?<=\s) (X)(?=\s)     | #010
                     (?<=\s) (X) (?=X)     | #011
                     (?<=X) (\s)(?=\s)     | #100
                     (?<=X)  \s (?=(X))    | #101
                     (?<=X)  (X)(?=\s)     | #110
                     (?<=X)   X  (?=X+(\s))| #111
                     (\s)$                   #End of line
                   /gx)]} ";
}