Fragment has a large selection of shapes called "fragments" that you can overlay your images with for unique results. In this picture, note the swipeable navigation bar of shapes at the bottom.
2 of 5 Screenshot by Jason Parker/CNET
Extra controls
From the same image-editing window, you can swipe up from the bottom to get to common controls such as brightness or contrast, and there's a wheel for selecting different colors.
3 of 5 Screenshot by Jason Parker/CNET
Color explosion
Though I went a little crazy here with bright colors, you can swipe the color wheel at the bottom for much finer adjustments.
4 of 5 Screenshot by Jason Parker/CNET
Toggle at the top
The circle at the top of the screen lets you toggle between editing the photo alone, and editing the fragment that overlays it.
5 of 5 Screenshot by Jason Parker/CNET
Share or keep working
When you're done with your project, you can share it via all the usual social-networking services or open it in other supported photo effects apps on your iOS device.