sub onTick {
    our $x;
    my $changed;
    # Initialize and associate $x with some external value
    foreach (@kabluther) {
      do { # these two lines must be a block - do together, or not at all.
        $x += $_->getSkookiness();
        $changed++;
      } # if clause can go here I think, if needed
    }
    if ($changed) {
      $_->ticked() for @listeners;
    }
    return $x;
  }