for my $i (0..3){
      $cell = $pmilecsquare if $pmis[$i] eq $o;
    }
[download]

should be the following to be equivalent:

    for my $i (0..3){
      if ($pmis[$i] eq $o) {
        $cell = $pmilecsquare;
        last;
      }
    }
[download]

which can be simplified to

    for (@pmis){
      if ($_ eq $o) {
        $cell = $pmilecsquare;
        last;
      }
    }
[download]