// Create a new shape
Aspose.Cells.Drawing.Shape polygonShape = xlWorkSheet.Shapes.AddAutoShape(Aspose.Cells.Drawing.AutoShapeType.RoundedRectangularCallout, 0, 0, 0, 0, 0, 0);
polygonShape.Y = 200; //Shape Top properties
polygonShape.X = 500; //Shape Left properties
polygonShape.Width = 200; // Shape Width
polygonShape.Height = 100; // Shape Height