<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Page.Resources>
    <DrawingBrush x:Key="DiamondBrush" TileMode="Tile">
      <DrawingBrush.Drawing>
        <DrawingGroup>

          <GeometryDrawing Brush="Black">
            <GeometryDrawing.Geometry>
              <GeometryGroup>
                <RectangleGeometry Rect="0,0,50,100" />
              </GeometryGroup>
            </GeometryDrawing.Geometry>
          </GeometryDrawing>
                    
          <GeometryDrawing Brush="DarkBlue">                        
            <GeometryDrawing.Geometry>
              <PathGeometry>
                <PathGeometry.Figures>                
                    <PathFigure StartPoint="0,50">
                      <LineSegment Point="25,0" />  
                      <LineSegment Point="50,50" />  
                      <LineSegment Point="25,100" />  
                      <LineSegment Point="0,50" />  
                    </PathFigure>
                </PathGeometry.Figures>
              </PathGeometry>
            </GeometryDrawing.Geometry>
          </GeometryDrawing>

        </DrawingGroup>
      </DrawingBrush.Drawing>
    </DrawingBrush>
  </Page.Resources>
  
  <Grid Background="{StaticResource DiamondBrush}">  
    
  </Grid>
  
</Page>