Sorry to be so long replying. It was largely because I wasn’t sure what to say. But one answer just occurred to me: inventing the concepts people make programs out of. Aka language design.
Long it was. I wrote him Aug 24, 2007 and he replied yesterday. Amazing that someone doesn’t just forget about an email after all this time.
If you don’t know him, the language design he talks about is Arc and i know him, because of his great essays. At least his older writings are good. The newer stuff doesn’t always reach the old quality.