[HelloSupport]

I want to display two overlapping rectangles.  I have written a sample project that does this (MainWindow.xaml) and the result is screenshot1.   However, I want the windows to look like screenshot2 (for clarity, I added labels in screenshot2 that indicate the rectangles' positions.)  There are two differences in screenshot2: the rectangles are arranged slightly differently and we do not see the edges of the "bottom" rectangle that is overlapped.  How can I re-write MainWindow.xaml so that I get the result in screenshot2?  Thanks for any help you can give.