I'm curious now, you have added the stair idea, but the shape you are talking about folds back on itself, therefore making it impossible to form a walkable staircase, unless your name is Escher.
Are you trying to make something like this?
I have downloaded extrude edges as well but not tried it yet. I have yet to try ferrari but am unsure if this brings anything else 'to the table' or whether it is doubling up with some of the other tools. Had also heard it was a bit unstable?