“What made oil paint so exciting, when it first became popular in the fifteenth century, was that you could make the finished work from the prototype. You could make a preliminary drawing if you wanted to, but you weren’t held to it; you could work out all the details, and even make major changes as you finished the painting. You can do this with software too. A prototype doesn’t have to be just a model; you can refine it into the finished product. [...] It’s good for morale.”