I would say a solid 55% of the film A Beautiful Mind is just Russell Crowe doing math on the walls, which perpetuates this idea of the genius being a total slob. I've tried explaining this to my landlord but he doesn't quite agree.
For my messy genius moments, I use MyScript Calculator. Simple, easy and intuitive, you can write straight in the calculator by hand and MyScript Calculator will do the rest, converting your handwritten work into digital and solving it in real-time. Simply brilliant! MyScript Calculator is FREE!