anchor.diff:                  return new Point(t.item1, t.item2);
                 })
                 .where((t) => game.getSquareState(t.x, t.y) == SquareState.hidden)
  -              .toList();
  +              .toList() as List<Point>;
   
             assert(adjHidden.length > 0);
   
  
positive.code:     if (reveals == null) {
        assert(game.state == GameState.lost);
  
        reveals = new Iterable.generate(game.field.length, (i) {
          var t = game.field.getCoordinate(i);
          var c = new Point(t.item1, t.item2);
          return new Tuple(c, game.getSquareState(c.x, c.y));
  
negative.code:           .where((t2) =>
                t2.item2 == SquareState.bomb || t2.item2 == SquareState.hidden)
            .map((t2) => t2.item1)
            .toList() as List<Point>;
      }
  
      final values = reveals.map((c) {
  