His idea is that the way to understand a <i>large</i> computer program is by running it, testing it. So he&#x27;s made (what I understand) a very nice UI for introspection of a running computer program. You can see what is happening while it&#x27;s running.<p>Designing a programming language is kind of like a &#x27;rite of passage.&#x27; I think most of us have at least thought about how to make languages better.