Canvas

I think this is about the minimum you need to draw a shape on a Canvas programmatically.

<Window x:Class="DrawStateMachineMap.Window2"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window2" Height="300" Width="300">
    <Grid>
      <Canvas Name="MainCanvas"></Canvas>
   </Grid>
</Window>

      public Window2()
      {
         InitializeComponent();

         Rectangle aRectangle = new Rectangle();
         aRectangle.Width = 100;
         aRectangle.Height = 50;
         aRectangle.Stroke = Brushes.Red;

         Canvas.SetLeft(aRectangle, 10);
         Canvas.SetTop(aRectangle, 15);

         MainCanvas.Children.Add(aRectangle);
      }