Wet Paint is another free drawing app for iPad and for Android users. I like this app not only because it is easy to use but it also has a Tic Tac Toe and dots template built within the app. You could use the dots template for drawing 3D shapes, drawing 2D shapes and identifying angles or even creating a grid reference. The only feature that I don’t like about the app is that if you use the eraser over the dot template the dots will erase.