anchor.diff:  
       Vector3 vertex;
   
  -    lines.forEach((String line) {
  -      line = line.replaceAll(new RegExp(r"\s+$"), "");
  -      List<String> chars = line.split(" ");
  +    lines.forEach((dynamic line) {
  +      String lline = line;
  +      lline = lline.replaceAll(new RegExp(r"\s+$"), "");
  +      List<String> chars = lline.split(" ");
   
         // vertex
         if (chars[0] == "v") {
  
positive.code:       verticesToDraw[i] = _calcDefaultVertex(verticesToDraw[i]);
      }
  
      final List avgOfZ = <Map>[];
      for (int i = 0; i < faces.length; i++) {
        List face = faces[i];
        double z = 0.0;
        face.forEach((int x) {
          z += verticesToDraw[x - 1].z;
        });
        Map data = <String, dynamic>{
          "index": i,
  
negative.code:       path.lineTo(secondVertexX, secondVertexY);
      }
      var z = 0.0;
      face.forEach((dynamic x) {
        int xx = x;
        z += verticesToDraw[xx - 1].z;
      });
  
      path.close();
  