anchor.diff:  class GameElement extends ElementParentImpl {
  +  static const _edgeOffset = 32;
  +
     final bool _targetMode;
     final dartlib.EventHandle _targetChanged;
   
  
positive.code: 
          // position the square
          final etx = se.addTransform();
          etx.setToTranslation(coords.Item1 * SquareElement._size, coords.Item2 * SquareElement._size);
  
          _elements[i] = se;
        }
  
negative.code:       size = const dartlib.Size(100, 100);
      } else {
        size = new dartlib.Size(
            SquareElement._size * value.field.width + _edgeOffset * 2,
            SquareElement._size * value.field.height + _edgeOffset * 2);
      }
    }
  
  