code: function Heart(desired_width) {
  
      var points = PixelWalker(STARTING_POINT, path);
      var pathModel = new makerjs.models.ConnectTheDots(true, points);
      if (typeof desired_width != 'undefined') {
          var scale = desired_width / HEART_WIDTH;
          makerjs.model.scale(pathModel, scale);
      }
      return pathModel;
  }
docs: Builds a pixel heart model and scale it to the specified input width.