sub good_sub_name_here {
  my ($color, $other_color) = @_;
  if ($old_color eq $color) {
    if ($_ == 1) {
      alert(1);
    } elsif ($button[$_-1]->cget(-background) eq $color) {
      alert(2);
    } elsif ($_ >= 2 && $button[$_-1]->cget(-background) eq $other_color && $button[$_-2]->c
+get(-background) ne "white") {
      alert(3);
    } elsif ($button[$_-1]->cget(-background) eq "white") {
      make_color ($color, $_-1);
      make_blank ($_);
      check_win();
    } else {
      make_color ($color, $_-2);
      make_blank ($_);
      check_win();
    }
  }
}

# and call it:
good_sub_name_here(qw(blue red))
good_sub_name_here(qw(red blue))