internal override XElement CreateXml()
{
var xRoot = new XElement(XmlConstants.Brick);
xRoot.SetAttributeValue(XmlConstants.Type, XmlConstants.XmlGoNStepsBackBrickType);
var xElement = StepsXML.CreateXml();
xElement.SetAttributeValue(XmlConstants.Category, XmlConstants.Steps);
var xFormulalist = new XElement(XmlConstants.FormulaList);
xFormulalist.Add(xElement);
xRoot.Add(xFormulalist);
return xRoot;
}