anchor.diff:          _rampName = name;
       }
   
  -    Uint8List _execute(PointCloudTile tile, double zmin, double zmax) {
  +    void _execute(PointCloudTile tile, double zmin, double zmax) {
           if (rampName == null || rampName.isEmpty) {
               throw new StateError("color ramp is null");
           }
   
  -        // TODO: reuse this every tile
  -        var newColors = new Uint8List(tile.numPointsInTile * 4);
  +        var rgba = tile.data["rgba"] as List;
   
           if (rampName == "native") {
               log(tile.data.keys);
  
positive.code: 
          PointCloud cloud = tile.cloud;
  
          Uint8List rgba = _execute(tile, cloud.bbox.minimum.height, cloud.bbox.maximum.height);
  
          tile.addData_U8x4("rgba", rgba);
          tile.updateBounds();
          tile.updateShape();
      }
  
negative.code:             assert(result.r >= 0 && result.r <= 255);
              assert(result.g >= 0 && result.g <= 255);
              assert(result.b >= 0 && result.b <= 255);
              rgba[i * 4 + 0] = result.r;
              rgba[i * 4 + 1] = result.g;
              rgba[i * 4 + 2] = result.b;
              rgba[i * 4 + 3] = 255;
          }
      }
  
      _Color _interpolate(double z, double startRange, double endRange, _Color startColor, _Color endColor) {
  