if ($old_color eq "red") {
    if ($_ == 11) {
      alert(1);
    } elsif ($button[$_+1]->cget(-background) eq "red") {
      alert(2);
    } elsif ($_ <= 9 && $button[$_+1]->cget(-background) eq "blue" && $button[$_+2]->cget(-background) ne "white") {
      alert(3);
    } elsif ($button[$_+1]->cget(-background) eq "white") {
      make_color ("red", $_+1);
      make_blank ($_);
      check_win();
    } else {
      make_color ("red", $_+2);
      make_blank ($_);
      check_win();
    }
  }

  if ($old_color eq "blue") {
    if ($_ == 1) {
      alert(1);
    } elsif ($button[$_-1]->cget(-background) eq "blue") {
      alert(2);
    } elsif ($_ >= 2 && $button[$_-1]->cget(-background) eq "red" && $button[$_-2]->cget(-background) ne "white") {
      alert(3);
    } elsif ($button[$_-1]->cget(-background) eq "white") {
      make_color ("blue", $_-1);
      make_blank ($_);
      check_win();
    } else {
      make_color ("blue", $_-2);
      make_blank ($_);
      check_win();
    }
  }