This document discusses different methods for prototyping mobile apps. It defines prototyping as a scenario-based simulation that allows users to experience aspects of a potential product. Paper prototyping involves sketching or wireframes, while screen-based prototyping uses clickable wireframes or interactive prototypes. The author's preference is to first understand the shape of the data flow and draw interaction flows and screens on paper before implementing the prototype. Tools mentioned include Fiddler, Visual Studio, and making portable data and service models. Storyboarding in PowerPoint 2013 is also referenced.