public CIMPolygonSymbol Symbol {get; set;}

//create marker from the Font, char index,size,color
var cimMarker = SymbolFactory.Instance.ConstructMarker(125, "Wingdings 3", "Regular", 6, ColorFactory.Instance.BlueRGB) as CIMCharacterMarker;
  var polygonMarker = cimMarker.Symbol;
  //modifying the polygon's outline and fill
  //This is the outline
  polygonMarker.SymbolLayers[0] = SymbolFactory.Instance.ConstructStroke(ColorFactory.Instance.GreenRGB, 2, SimpleLineStyle.Solid);
  //This is the fill
  polygonMarker.SymbolLayers[1] = SymbolFactory.Instance.ConstructSolidFill(ColorFactory.Instance.BlueRGB);
  //create a symbol from the marker 
  //Note this overload of ConstructPointSymbol does not need to be run within QueuedTask.Run.
  var pointSymbol = SymbolFactory.Instance.ConstructPointSymbol(cimMarker);