Animation with StoryBoard in WPF

<Window x:Class="WpfApplication1.Window6"

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

        Title="Window6" Height="300" Width="300">

    <Window.Resources>

        <Storyboard x:Key="rotatebeh"  RepeatBehavior="Forever">

                    <DoubleAnimation Storyboard.TargetProperty="Width" Storyboard.TargetName="Button1"

      From="50" To="100" AutoReverse="True" Duration="0:0:5" ></DoubleAnimation>

                    <DoubleAnimation Storyboard.TargetProperty="Height"  Storyboard.TargetName="Button1"

      From="20" To="30" AutoReverse="True" Duration="0:0:5"></DoubleAnimation>

                </Storyboard>

            

      

    </Window.Resources>

    <Grid>

        

        <Button Content="Start" x:Name="Button1" HorizontalAlignment="Left" Margin="97,72,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_1"/>

        <Rectangle x:Name="rectangle1" Fill="#FFF4F4F5" HorizontalAlignment="Left" Height="100" Margin="97,161,0,0" Stroke="Black" VerticalAlignment="Top" Width="100"/>

        <Button Content="Stop" x:Name="Button2" HorizontalAlignment="Left" Margin="195,72,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_2">

            

        </Button>

        <Button Content="Button" HorizontalAlignment="Left" Margin="35,55,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_3"/>

        <Button Content="Button" HorizontalAlignment="Left" Margin="17,199,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click_4"/>

        <Button Height="23" Margin="102,95,100,0" Name="button3" VerticalAlignment="Top" Content="Opacity" Click="button3_Click">

            <Button.Triggers>

                <EventTrigger RoutedEvent="Button.Click">

                    <BeginStoryboard>

                        <Storyboard>

                            <DoubleAnimation Storyboard.TargetName="button3"

                                             Storyboard.TargetProperty="Opacity"

                                             From="1"

                                             To="0"

                                             Duration="0:0:2"

                                             AutoReverse="True"

                                             RepeatBehavior="3x"/>

                        </Storyboard>

                    </BeginStoryboard>

                </EventTrigger>

            </Button.Triggers>

        </Button>

    </Grid>

</Window>