GraphicElement CreateRectangleParagraphGraphicElement( 
   ILayoutElementContainer elementContainer,
   Envelope envelope,
   string text
)

//Create rectangle text with background and border symbology.  

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //Build 2D polygon geometry
  List<Coordinate2D> plyCoords = new List<Coordinate2D>();
  plyCoords.Add(new Coordinate2D(3.5, 7));
  plyCoords.Add(new Coordinate2D(4.5, 7));
  plyCoords.Add(new Coordinate2D(4.5, 6.7));
  plyCoords.Add(new Coordinate2D(5.5, 6.7));
  plyCoords.Add(new Coordinate2D(5.5, 6.1));
  plyCoords.Add(new Coordinate2D(3.5, 6.1));
  Polygon poly = PolygonBuilder.CreatePolygon(plyCoords);

  //Set symbolology, create and add element to layout
  //Also notice how formatting tags are using within the text string.
  CIMTextSymbol sym = SymbolFactory.Instance.ConstructTextSymbol(ColorFactory.Instance.GreyRGB, 10, "Arial", "Regular");
  string text = "Some Text String that is really long and is <BOL>forced to wrap to other lines</BOL> so that we can see the effects." as String;
  GraphicElement polyTxtElm = LayoutElementFactory.Instance.CreatePolygonParagraphGraphicElement(layout, poly, text, sym);
  polyTxtElm.SetName("New Polygon Text");

  //(Optionally) Modify paragraph border 
  CIMGraphic polyTxtGra = polyTxtElm.Graphic;
  CIMParagraphTextGraphic cimPolyTxtGra = polyTxtGra as CIMParagraphTextGraphic;
  cimPolyTxtGra.Frame.BorderSymbol = new CIMSymbolReference();
  cimPolyTxtGra.Frame.BorderSymbol.Symbol = SymbolFactory.Instance.ConstructLineSymbol(ColorFactory.Instance.GreyRGB, 1.0, SimpleLineStyle.Solid);
  polyTxtElm.SetGraphic(polyTxtGra);
});