I think one of the interesting things is that vi is really a mode-based editor.
I was surprised about vi going in, though, I didn't know it was in System V.
It is formatted, and I'm tired of using vi. I get really bored.
You can't prove anything about a program written in C or FØRTRAN. It's really just Peek and Poke with some syntactic sugar.
I think the Macintosh proves that everyone can have a bitmapped display.
Sometimes the easiest way to get something done is to be a little naive about it.