public LineElement AddLine(Vector fromVector, Vector toVector, int width, Color color)
        {
            var lineElement = new LineElement(fromVector, toVector, width, color);
            this.elements.Add(lineElement);

            return lineElement;
        }
 private static XElement ToXml(LineElement lineElement)
 {
     return new XElement("LineElement",
         new XAttribute("from", lineElement.FromVector),
         new XAttribute("to", lineElement.ToVector),
         new XAttribute("width", lineElement.Width),
         new XAttribute("color", lineElement.Color));
 }