Pulsating Rectangle

   
     

<Canvas xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Rectangle Name="rect"
               Canvas.Left="96" Canvas.Top="96" 
               Width="192" Height="192"
               Stroke="Black">

    </Rectangle>

    <Canvas.Triggers>
        <EventTrigger RoutedEvent="Canvas.Loaded">
            <BeginStoryboard>
                <Storyboard>
                    <DoubleAnimation Storyboard.TargetName="rect"
                                     Storyboard.TargetProperty="Width"
                                     From="192" To="204" Duration="0:0:0.1"
                                     AutoReverse="True"
                                     RepeatBehavior="Forever" />

                    <DoubleAnimation Storyboard.TargetName="rect"
                                     Storyboard.TargetProperty="Height"
                                     From="192" To="204" Duration="0:0:0.1"
                                     AutoReverse="True"
                                     RepeatBehavior="Forever" />

                    <DoubleAnimation Storyboard.TargetName="rect"
                                     Storyboard.TargetProperty="(Canvas.Left)"
                                     From="96" To="90" Duration="0:0:0.1"
                                     AutoReverse="True"
                                     RepeatBehavior="Forever" />

                    <DoubleAnimation Storyboard.TargetName="rect"
                                     Storyboard.TargetProperty="(Canvas.Top)"
                                     From="96" To="90" Duration="0:0:0.1"
                                     AutoReverse="True"
                                     RepeatBehavior="Forever" />


                </Storyboard>
            </BeginStoryboard>
        </EventTrigger>
    </Canvas.Triggers>
</Canvas>