Sketching a Scenario As A Smartphone Application

While thinking about a scenario in your product story and wondering how it flows, it is easier, and now-a-days necessary, to think mobile first. A few days back, I shared a story of a mother collaborating with her son's pediatrician using an application called Doctor's place. This is how I visualized one scene in that story where the mother messages the nurse to check on the status of her son's X-Ray.

I normally sketch these by hand. You could also use Balsamiq, a prototyping tool.