This hugely popular app for quick sketches provides many useful functions like Undo/Redo, changing the background color, or using an image as the background. You can optionally make the app prevent the device from falling asleep too. You can also change the brush size, or use an eraser, if you messed something up. It supports inserting colors either by selecting it on a huge palette, or by entering the colors hex code. This app will suit you perfectly. Just pick a color and draw, it is...