Another thing that you need to get straight is the GDI+ coordinate system. If you have studied math and geometry, you may be used to a coordinate system that looks like this.
But GDI+ uses a forms based coordinate system where the "origin" is in a different corner. And, although you can assign negative numbers to the coordinates without generating an error, they're "off the form" and don't show up. While you're experimenting, you might want to try it.
