sub pascal {
   my $max    = shift or return;
   my @row    = (0) x $max;
      $row[0] = 1;
   foreach (1 .. $max) {
       print " " x ($max - $_),"@row[0 .. $_ - 1]\n";
       $row[$_] += $row[$_ - 1] for reverse 1 .. @row;
   }
}