Paints a rectangle with a grid pattern

   
     

<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">
      <Rectangle Width="50" Height="50" Grid.Row="1" Grid.Column="1">
        <Rectangle.Fill>
          <DrawingBrush Viewport="0,0,10,10" ViewportUnits="Absolute" TileMode="Tile">
            <DrawingBrush.Drawing>
              <DrawingGroup>
                <GeometryDrawing Brush="White">
                  <GeometryDrawing.Geometry>
                    <RectangleGeometry Rect="0,0,1,1" />
                  </GeometryDrawing.Geometry>
                </GeometryDrawing>
                <GeometryDrawing Brush="Blue"
                  Geometry="M 0,0 L 0,1 0.1,1 0.1,0.1 1,0.1 1,0 Z" />
              </DrawingGroup>
            </DrawingBrush.Drawing>
          </DrawingBrush>
        </Rectangle.Fill>
      </Rectangle>

</Window>