Simulating lighting effects with linear fills

   
             

<Page xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
      xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
      HorizontalAlignment="Center" VerticalAlignment="Center">

    <Grid Width="80" Height="26">
        <Grid.RowDefinitions>
            <RowDefinition Height="2*" />
            <RowDefinition Height="*" />
        </Grid.RowDefinitions>

        <Rectangle Grid.RowSpan="2" RadiusX="13" RadiusY="13">
            <Rectangle.Fill>
                <LinearGradientBrush StartPoint="0,0" EndPoint="0,1">
                    <GradientStop Color="Green" Offset="0" />
                    <GradientStop Color="DarkGreen" Offset="0.5" />
                </LinearGradientBrush>
            </Rectangle.Fill>
        </Rectangle>
    </Grid>
</Page>