“When I make a demo, I think about the intended audience, and I make a specific decision about what features to include. I draw a conceptual ring around those key details, and I use a thick imaginary marker to do it. The demo points inside the ring are the focus, and like the lamppost in the movie scene, I depict them with the highest fidelity. I leave outside the ring other less important details that will eventually have to be addressed, but not immediately. I pay them as little attention as possible.”