[Alli Dryer details her 10 step process for prototyping with](http://badyewex.com/words/2013/2/21/10-steps-to-prototyping-with-pop-app), the new to me, app [POP](http://itunes.com/apps/woomoo/pop-prototyping-on-paper/):

>With POP, you snap photos of your freehand sketches, bring them to life by linking them together to simulate the user experience, and then easily share your prototype with others.

This looks like a fantastic way to flesh out an idea, or ideas, for iOS apps. Very clever app.