Xaml Physics makes it possible to make a physics simulation with only xaml code. It is a wrapper around the Farseer Physics Engine.
<Physics:PhysicalBox x:Name="PhysicalBox">
<Rectangle Canvas.Top="100" Canvas.Left="0" Width="400" Height="30" Fill="Black">
<Physics:PhysicalBox.Body>
<Physics:RectangleBody IsStatic="True" />
</Physics:PhysicalBox.Body>
</Rectangle>
<Rectangle Canvas.Top="0" Canvas.Left="20" Width="10" Height="10" Fill="Black">
<Physics:PhysicalBox.Body>
<Physics:RectangleBody />
</Physics:PhysicalBox.Body>
</Rectangle>
</Physics:PhysicalBox>http://liserdartsgames.com/LocalResources/XamlPhysics/Index.html