OneView2

This app likely is quite good if you know all about the .pdf apps that are out there. If you start from little to no such knowledge, as I do, the instructions with this app are not much use at all. They do cute little things to illustrate individual icons—which is to say they describe individual trees—but they do next to nothing, in my opinion, to show you the forest. In other words, there’s no useful overview. You just have to try every imaginable icon and hope to somehow guess how they all interact in useful ways.