WPF

System.Timers.Timer aTimer = new 
                   System.Timers.Timer(1000);
public Window1()
{
    InitializeComponent();

    aTimer.Elapsed += new 
         System.Timers.ElapsedEventHandler
                        (aTimer_Elapsed);            
    aTimer.Enabled = true;
}

void aTimer_Elapsed(object sender, 
          System.Timers.ElapsedEventArgs e)
{
    secondHand.Angle = DateTime.Now.Second * 6;
}

<Rectangle Margin="150,0,149,150" 
Name="rectangleSecond" Stroke="White" 
Height="120" VerticalAlignment="Bottom"
><Rectangle.RenderTransform>
<RotateTransform x:Name="secondHand" 
CenterX="0" CenterY="120" 
Angle="0" />
</Rectangle.RenderTransform>
</Rectangle>

The calling thread cannot access this object because a different 
thread owns it.