public enum PredefinedShape : System.Enum, System.IComparable, System.IConvertible, System.IFormattable, System.ISpanFormattable  

{
  //Create a simple 2D rectangle graphic and apply simple fill and
  //outline symbols.

  //Note: Must be on QueuedTask.Run

  //Build 2D envelope geometry
  Coordinate2D rec_ll = new Coordinate2D(1.0, 4.75);
  Coordinate2D rec_ur = new Coordinate2D(3.0, 5.75);

  Envelope rec_env = EnvelopeBuilderEx.CreateEnvelope(rec_ll, rec_ur);

  //Set symbology, create and add element to layout
  CIMStroke outline = SymbolFactory.Instance.ConstructStroke(
    ColorFactory.Instance.BlackRGB, 5.0, SimpleLineStyle.Solid);
  CIMPolygonSymbol polySym = SymbolFactory.Instance.ConstructPolygonSymbol(
    ColorFactory.Instance.GreenRGB, SimpleFillStyle.DiagonalCross, outline);


  GraphicElement recElm = ElementFactory.Instance.CreateGraphicElement(
    layout, rec_env, polySym, "New Rectangle");
  //Or use Predefined shape
  GraphicElement recElm2 = ElementFactory.Instance.CreatePredefinedShapeGraphicElement(
                            layout, PredefinedShape.Rectangle, rec_env, polySym,
                            "New Rectangle2");
}

{
  PredefinedShape shapeType = PredefinedShape.Circle;
  //Note: Must be on QueuedTask.Run

  //PredefinedShape shapeType =
  //              PredefinedShape.Circle | Cloud | Cross |Circle | Triangle | ... ;

  //Build geometry
  Coordinate2D ll = new Coordinate2D(4, 2.5);
  Coordinate2D ur = new Coordinate2D(6, 4.5);
  Envelope env = EnvelopeBuilderEx.CreateEnvelope(ll, ur);

  var outline = SymbolFactory.Instance.ConstructStroke(
                  ColorFactory.Instance.BlueRGB, 2);
  var poly_sym = SymbolFactory.Instance.ConstructPolygonSymbol(
                   null, outline);

  var ge = ElementFactory.Instance.CreatePredefinedShapeGraphicElement(
                         layout, shapeType, env.Center, env.Width, env.Height,
                          poly_sym, shapeType.ToString(), true);
}

{
  //Note: Must be on QueuedTask.Run

  //Build geometry
  Coordinate2D ll = new Coordinate2D(6.5, 7);
  Coordinate2D ur = new Coordinate2D(9, 9);
  Envelope env = EnvelopeBuilderEx.CreateEnvelope(ll, ur);

  var outline = SymbolFactory.Instance.ConstructStroke(
                  ColorFactory.Instance.GreenRGB, 2);
  var poly_sym = SymbolFactory.Instance.ConstructPolygonSymbol(
                   null, outline);

  var ge = ElementFactory.Instance.CreatePredefinedShapeGraphicElement(
    layout, PredefinedShape.RoundedRectangle, env, poly_sym, "Rounded Rect", true);
}

{
  //Note: Must be on QueuedTask.Run

  //Build geometry
  Coordinate2D center = new Coordinate2D(2, 2.75);
  var eabElp = new EllipticArcBuilderEx(
                           center, 0, 1, 0.45, ArcOrientation.ArcClockwise);
  var ellipse = eabElp.ToSegment();

  //Set symbology, create and add element to layout
  CIMStroke outline = SymbolFactory.Instance.ConstructStroke(
                        ColorFactory.Instance.GreenRGB, 2.0, SimpleLineStyle.Dot);
  CIMPolygonSymbol ellipseSym = SymbolFactory.Instance.ConstructPolygonSymbol(
                   ColorFactory.Instance.GreyRGB, SimpleFillStyle.Vertical, outline);

  var poly = PolygonBuilderEx.CreatePolygon(
    PolylineBuilderEx.CreatePolyline(ellipse, AttributeFlags.AllAttributes));

  var ge = ElementFactory.Instance.CreatePredefinedShapeGraphicElement(
    layout, PredefinedShape.Ellipse, poly.Extent.Center, 0, 0, ellipseSym,
    "New Ellipse2", false, new ElementInfo() { Anchor = Anchor.TopRightCorner });
}