anchor.diff:    Map<int, BasicTile> basicTiles;
     Map<int, Tile> tileset;
   
  -  /// Creates a new tilemap from a JSON map
  +  /// Creates a new tilemap from a TMX map
     Tilemap(this.file) {
       this.width = int.parse(file.rootElement.getAttribute("width"));
       this.height = int.parse(file.rootElement.getAttribute("height"));
  
positive.code:   int width;
    int height;
  
    /// Creates a new tile layer from JSON data
    TileLayer(this.layer, this.parent) {
      width = int.parse(layer.getAttribute("width"));
      height = int.parse(layer.getAttribute("height"));
  
negative.code: part of cobblestone;
  
  /// Loads a TMX tilemap from a URL. Use Tiled to create these. (http://www.mapeditor.org/)
  Future<Tilemap> loadTilemap(String url) {
    return HttpRequest
        .getString(url)
  