<Window x:Class="WpfApplication1.Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="WPF" Height="350" Width="300"> <UniformGrid Columns="3" HorizontalAlignment="Center" VerticalAlignment="Center"> <Rectangle Stroke="Black" StrokeThickness="3" Height="100" Width="70" RadiusX="10" RadiusY="10"/> </UniformGrid> </Window>