HEREMap.prototype.addMarker = function(coordinates, icon) {
  var markerOptions = {};

  var icons = {
    iceCream: {
      url: './images/marker-gelato.svg',
      options: {
        size: new H.math.Size(26, 34),
        anchor: new H.math.Point(14, 34)
      }
    },
    origin: {
      url: './images/origin.svg',
      options: {
        size: new H.math.Size(30, 36),
        anchor: new H.math.Point(12, 36)
      }
    },
    destination: {
      url: './images/destination.svg',
      options: {
        size: new H.math.Size(30, 36),
        anchor: new H.math.Point(12, 36)
      }
    }
  };

  if (icons[icon]) {
    markerOptions = {
      icon: new H.map.Icon(icons[icon].url, icons[icon].options)
    };
  }

  var marker = new H.map.Marker(coordinates, markerOptions);
  this.map.addObject(marker);

	return marker;
};