Rotates the Polyline 45 degrees about the point (25,50)

   
     
<Window x:Class="Workspace.DockExample"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Workspace" Width="640" Height="480">
          <Polyline Points="25,25 0,50 25,75 50,50 25,25 25,0" 
            Stroke="Blue" StrokeThickness="10">
            <Polyline.RenderTransform>
              <RotateTransform CenterX="25" CenterY="50" Angle="45" />
            </Polyline.RenderTransform>
          </Polyline>

</Window>