    $_="123456"; 
    for $n (1..12) {
      for $i (1..6) {
        do {
          $r = int(rand($l=length($_)));
          s/(.{$r})(.*)/$2$1/;
        } until s/^([^$i]{2})([^$i]{2})/$1$i$2/;
      }
    }
    print "$_\n";

    for $i (1..6) {
      $o = $_;
      $o =~ s/[^$i]/./g;
      print "$o\n";
    }
