C# WinForms RichTextText Block-Style Selection

Question

Hi all.


Interested in such a thing:
Is it possible to do block allocation (as in the pictures) in WinForms RichTextBox?
If you can, then about how this is done?


p.s. know what is being done through OnPaint, Graphics.. but how exactly is the drawing of a border on the sides?

Example (Image) http://tinypic.com/view.php?pic=28qtgxz&s=8