Inline visual outputs improve our ability to inspect the program’s current state. Interactive programming improves our ability to scrutinize behavior by poking: changing, deleting, reordering code, and seeing what happens. For example, by commenting out forces in the force-directed graph below, we get a better sense of t…

…on could be interspersed with unrelated code, impeding readability. In reactive programming, we can localize the definition and let the runtime manage execution order: