<Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="WpfApplication1" Height="352" Width="334" WindowStartupLocation="CenterScreen"> <StackPanel> <Polygon Fill ="AliceBlue" StrokeThickness ="5" Stroke ="Green" Points ="40,10 70,80 10,50" /> </StackPanel> </Window>