code: function normalizeMarker(d, offset) {
      var path = new g.Path(V.normalizePathData(d));
      var bbox = path.bbox();
      var ty = - bbox.height / 2 - bbox.y;
      var tx = - bbox.width / 2 - bbox.x;
      if (typeof offset === 'number') tx -= offset;
      path.translate(tx, ty);
      return path.serialize();
  }
docs: Utility function for normalizing marker's path data. Translates the center of an arbitrary path at <0 + offset,0>.