A rectangle with a rotate transformation

   
     
<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:sys="clr-namespace:System;assembly=mscorlib" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
  <Grid>

    <Rectangle Height ="100" Width ="40" Fill ="Red" Grid.Row="0" Grid.Column="0">
      <Rectangle.LayoutTransform>
        <RotateTransform Angle ="45"/>
      </Rectangle.LayoutTransform>
    </Rectangle>

  </Grid>

</Window>