<Page
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Page.Resources>

    <LinearGradientBrush x:Key="MainFillGradient" StartPoint="0,0" EndPoint="0,1">
      <GradientStop Offset="0.0" Color="DarkBlue" />
      <GradientStop Offset="1.0" Color="Black" />
    </LinearGradientBrush>
    
    <LinearGradientBrush x:Key="DiamondFillGradient" StartPoint="0,0" EndPoint="0,1">
      <GradientStop Offset="0.0" Color="#334444FF" />
      <GradientStop Offset="1.0" Color="#338888FF" />    
    </LinearGradientBrush>
    
    <DrawingBrush x:Key="DiamondBrush" TileMode="Tile" ViewportUnits="Absolute" Viewport="0,0,25,25">
      <DrawingBrush.Drawing>
        <DrawingGroup>                    
          <GeometryDrawing Brush="{StaticResource DiamondFillGradient}">                        
            <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 MainFillGradient}">  
    <Grid Background="{StaticResource DiamondBrush}" />
  </Grid>
</Page>