<Canvas xmlns:local="clr-namespace:WPFTester"> 
    <Canvas.Resources> 
      <Style TargetType="Ellipse"> 
        <Setter Property="Width" Value="{x:Static local:PointsConverter.PointWidth}" /> 
        <Setter Property="Height" Value="{x:Static local:PointsConverter.PointWidth}" /> 
        <Setter Property="Cursor" Value="SizeAll" /> 
        <Setter Property="Fill" Value="Blue" /> 
        <EventSetter Event="MouseLeftButtonDown" Handler="Element_MouseLeftButtonDown" /> 
        <EventSetter Event="MouseMove" Handler="Element_MouseMove" /> 
        <EventSetter Event="MouseLeftButtonUp" Handler="Element_MouseLeftButtonUp" /> 
      </Style> 
      <local:PointsConverter x:Key="PointsConverter" /> 
    </Canvas.Resources> 
    <Polygon Fill="Red"> 
      <Polygon.Points> 
        <MultiBinding Mode="TwoWay" Converter="{StaticResource PointsConverter}"> 
          <Binding ElementName="P1" Path="(Canvas.Left)" /> 
          <Binding ElementName="P1" Path="(Canvas.Top)" /> 
          <Binding ElementName="P2" Path="(Canvas.Left)" /> 
          <Binding ElementName="P2" Path="(Canvas.Top)" /> 
          <Binding ElementName="P3" Path="(Canvas.Left)" /> 
          <Binding ElementName="P3" Path="(Canvas.Top)" /> 
          <Binding ElementName="P4" Path="(Canvas.Left)" /> 
          <Binding ElementName="P4" Path="(Canvas.Top)" /> 
          <Binding ElementName="P5" Path="(Canvas.Left)" /> 
          <Binding ElementName="P5" Path="(Canvas.Top)" /> 
        </MultiBinding> 
      </Polygon.Points> 
    </Polygon> 
    <Ellipse Name="P1" Canvas.Left="50" Canvas.Top="50" /> 
    <Ellipse Name="P2" Canvas.Left="150" Canvas.Top="150" /> 
    <Ellipse Name="P3" Canvas.Left="250" Canvas.Top="250" /> 
    <Ellipse Name="P4" Canvas.Left="50" Canvas.Top="150" /> 
    <Ellipse Name="P5" Canvas.Left="150" Canvas.Top="50" /> 
  </Canvas>