anchor.diff:    dartlib.EventRoot get targetChanged => _targetChanged;
   
     int get visualChildCount {
  -    var count = 1;
  +    var count = 2;
       if(_elements != null) {
         count +=_elements.length;
       }
  
positive.code:       final squareOffset = _popExplodeAnimationOffset +
            new dartlib.Vector(SquareElement._size * c.x, SquareElement._size * c.y);
  
        final delay = ((c - start).length * 4).toInt();
  
        final ss = game.getSquareState(start.x, start.y);
  
  
negative.code:   static const _backgroundHoleSize = 16 * SquareElement._size + 2 * _edgeOffset;
    static const _boardOffset = const dartlib.Vector(352, 96);
    static const _popExplodeAnimationOffset = const dartlib.Vector(-88, -88);
    static const _popAnimationHitFrame = 12;
  
    static const _dartAnimationOffset =
        const dartlib.Vector(-1065 + SquareElement._size ~/ 2,
            -815 + SquareElement._size ~/ 2);
  
  
    final TextureAnimationElement _popAnimationLayer, _dartAnimationLayer;
    final bool _targetMode;
    final dartlib.EventHandle _targetChanged;
  
    dartlib.AffineTransform _popLayerTx, _dartLayerTx;
    int _targetX, _targetY;
    double _scale;
    dartlib.Vector _scaledBoardOffset;
  