Use the RectangleBody class to create a rectangle. If no width or height is set the width and height of the FrameworkElement will be used.
Use the CircleBody class to create a circle. If no radius is set half the width of the FrameworkElement will be used.
Use the PolygonBody class to create a polygon. If no points are given and the PolygonBody body is applied to a Polygon, it's points will be used.