Differential dataflow programs are structured as two easy steps:
1. Write a program. 2. Change its input.
We will work through an example program, and then interact with it by changing its inputs. Our goal is foremost to show you what a program looks like, and to give you a sense for what interactions look like.
Once we've done this, in the next chapter we will jazz things up a bit with an increased scale of data, computation, and interaction!