Rotate then Translate

   
  

<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">

        <Canvas Height="200" Width="200">
          <Polyline
            Points="25,25 0,50 25,75 50,50 25,25 25,0" Stroke="Blue" StrokeThickness="10"
            Canvas.Left="75" Canvas.Top="50">
            <Polyline.RenderTransform>
                <TransformGroup>
                    <TransformGroup.Children>
                        <TransformCollection>
                            <RotateTransform CenterX="25" CenterY="50" Angle="45" />
                            <TranslateTransform X="50" Y="0" />
                        </TransformCollection>
                    </TransformGroup.Children>
               </TransformGroup>
            </Polyline.RenderTransform>
          </Polyline>
          <Polyline Points="25,25 0,50 25,75 50,50 25,25 25,0" Stroke="Blue" StrokeThickness="10"
            Opacity="0.25" Canvas.Left="75" Canvas.Top="50" /> 
        </Canvas>

</Window>