I felt the need for some practice this weekend so here's a little idea I knocked up this afternoon. I looked at an old app idea I'm planning to rework, but with little time and as I haven't done any icon work in a while or tried out the iOS 7 grid, I couldn't help myself.
The basic idea is to convey the users progress, the start of the progress bar gradually being completed and becoming a check mark. This will be clear in context with the UI but I'm sure both will progress dramatically.
Check out the attachment with the grid, it worked better when I used it pretty loosely. It's also got the iPhone view.
As with all first versions your feedback is much appreciated.