\di to start DrawIt and \ds to stop DrawIt.
The alpha/beta version is available at http://www.drchip.org/astronaut/vim/index.html#DRAWIT.
the ellipse and \e to trigger the ellipse drawing.
DrawIt incorporates an "erase" mode, toggled by the key, that will leave a trail of blanks behind and under the cursor as it is moved by the number pad. Using the shift-arrow keys, DrawIt will move the cursor, expanding lines and inserting spaces as needed, without changing underlying text.