Silverlight, WPF Brushes

SolidColorBrush LinearGradientBrush and RadialGradientBrush

<Rectangle Height="94" HorizontalAlignment="Left" Margin="57,42,0,0" Name="rectangle1" Stroke="Black" StrokeThickness="1" VerticalAlignment="Top" Width="201">
<Rectangle.Fill>
    <SolidColorBrush Color="Blue"/>
  
</Rectangle.Fill>

</Rectangle>
<Rectangle Height="92" HorizontalAlignment="Left" Margin="309,41,0,0" Name="rectangle2" Stroke="Black" StrokeThickness="1" VerticalAlignment="Top" Width="210">
<Rectangle.Fill>
    <LinearGradientBrush>
        <GradientStop Color="Blue" Offset="0"/>
        <GradientStop Color="Red" Offset="1"/>
    </LinearGradientBrush>
</Rectangle.Fill>
</Rectangle>

<Rectangle Height="80" HorizontalAlignment="Left" Margin="58,172,0,0" Name="rectangle3" Stroke="Black" StrokeThickness="1" VerticalAlignment="Top" Width="201">
<Rectangle.Fill>
    <RadialGradientBrush>
        <GradientStop Color="Blue" Offset="0"/>
        <GradientStop Color="Red" Offset="1"/>
    </RadialGradientBrush>
</Rectangle.Fill>
</Rectangle>
</Grid>