I have been coding on paper for 1 week, it is actually a very interesting exercise, it is sharpening my programming abstraction skills, I recommend any programmer to do that once a year.
It does force you to think about what you will code a lot more in your mind, and have a more complete idea of how it should work before coding it. I coded a GPU based physic engine for Humangnify, assembling physic rules and Forced driven graph, and using it as a decision voting system to decide how to display tweets. Demo soon!