This app has all the power and ease of use you need, as well as a unified the experience using Android and iOS. Sketchbook comes with a variety of drawing tools and brushes, all of which you can customise on the fly, pinch to zoom, a gallery organiser, and support for saving and storing your works to Dropbox or iCloud. In addition, users can create a free Sketchbook account to gain access to more features such as layering and symmetry tools.