Rectangle Geometry Demo

   
     

<Canvas xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Path Fill="Blue" Stroke="Red" StrokeThickness="3">
        <Path.Data>
            <RectangleGeometry Rect="96 48 288 192"
                               RadiusX="24" RadiusY="24" />
        </Path.Data>
    </Path>
</Canvas>