So in the growing number of apps dealing with drawing and writing, what is a good one that has plenty of focus and support on writing on graph paper? I'd like to be able to zoom in and out on the graph paper, with the grid scaling along the way. Ideally I could toggle between freehand on the graph paper and also be able to "snap to grid" so that the app will straiten out lines that I draw along the grid lines. It would also be nice to be able to include typed notes that I can insert around, basically mixing between freehand, typed, and computer aided straightening of lines all in one package. I'd probably be using a pogo sketch stylus most of the time.