Regarding using pen and paper, for certain tasks, I'm never fully satisfied with either working on paper or doing it on a computer.<p>For things like UI, mapping out the basic architecture of an app, on one hand I find that pen and paper is much faster and more convenient: you can scribble notes here and there, easily scratch out parts, draw arrows; but on the other, I wish it were more digital to reorganize things: make more room here, duplicate this, move that...<p>With software, if I want to add a small note, I need to select a different font or a different tool, click where I want to put it... On paper, I can just write smaller.<p>But on paper, if I realize that I need to add an element in between two others, the best way is often times to start all over again,<p>So neither are perfect, but maybe some touch interfaces will get us there.