I am looking for an app on which to do "back of the envelope" type equation scribbles. I would be writing on a blank background with my finger. It would essentially just be a whiteboard on an iPhone. Nothing fancy - no need for sharing etc... In fact it might be better without fancy features (more likely to be free, no annoying icons filling the screen) I would love it if someone who actually uses such an app could recommend one. The things I'm finding from searching on Google don't look quite right. There's no way to scroll down for instance. You're only given one page to draw on. Thanks!