How do I create repeating diagonal lines as a background in WPF?

Question

OK, I've wracked my brain, Google, and stackoverflow trying to figure this out, but just can't quite get it. I'm trying to use a DrawingBrush with a DrawingGroup to do two things to the background of my WPF application (latest version). One, I want to have a RadialGradientBrush to put a subtle gradient in my background. This part is working just fine. The second part that I'm trying to accomplish is that I want to also have repeating diagonal lines as part of that background. I know I could do it with an image, but would rather use geometries, as I'm trying to learn and master WPF. Here's what I have so far. The radial appears fine, but the lines do not. Any help would be appreciated.

<Style x:Key="WindowBackground" TargetType="Grid">
        <Setter Property="Background">
            <Setter.Value>
                <DrawingBrush>
                    <DrawingBrush.Drawing>
                        <DrawingGroup>
                            <GeometryDrawing>
                                <GeometryDrawing.Brush>
                                    <RadialGradientBrush GradientOrigin="0.5,0.5" RadiusX="0.5" RadiusY="0.5">
                                        <GradientStop Color="#EE9D40" Offset="0"/>
                                        <GradientStop Color="#BF8230" Offset="1"/>
                                    </RadialGradientBrush>
                                </GeometryDrawing.Brush>
                                <GeometryDrawing.Geometry>
                                    <RectangleGeometry Rect="0,0,1,1"/>
                                </GeometryDrawing.Geometry>
                            </GeometryDrawing>
                            <GeometryDrawing>
                                <GeometryDrawing.Brush>
                                    <DrawingBrush TileMode="Tile" Stretch="None" Viewbox="0,0,1,1" Viewport="0,0,25,25" ViewportUnits="Absolute">
                                        <DrawingBrush.RelativeTransform>
                                            <TranslateTransform X="0" Y="0" />
                                        </DrawingBrush.RelativeTransform>
                                        <DrawingBrush.Drawing>
                                            <GeometryDrawing Brush="#20FFFFFF" Geometry="M10,0 22,0 12,25 0,22 Z" />
                                        </DrawingBrush.Drawing>
                                    </DrawingBrush>
                                </GeometryDrawing.Brush>
                                <GeometryDrawing.Geometry>
                                    <RectangleGeometry Rect="0,0,1,1"/>
                                </GeometryDrawing.Geometry>
                            </GeometryDrawing>
                        </DrawingGroup>
                    </DrawingBrush.Drawing>
                </DrawingBrush>
            </Setter.Value>
        </Setter>
    </Style>

Answer 1

This trick should work.

<LinearGradientBrush EndPoint="0,0" StartPoint="8,8" 
                     MappingMode="Absolute" SpreadMethod="Repeat">
    <GradientStop Color="Black" Offset="0" />
    <GradientStop Color="Black" Offset="0.1" />
    <GradientStop Color="White" Offset="0.1" />
    <GradientStop Color="White" Offset="1" />
</LinearGradientBrush>