Here's the first that blew my mind, from the early 1980s: It was a BASIC "AI" program that would guess what animal you were thinking of just by asking a few que

Here's the first that blew my mind, from the early 1980s: It was a BASIC "AI" program that would guess what animal you were thinking of just by asking a few questions. "That's crazy," I thought. And, it learned more each time you ran it - even more crazy! It was only when I looked at the source code and realized that it was using self-modifying code that I went, "Wait a minute - THAT'S A THING?" I had so many of those moments. The very first was realizing you could use an iterator variable to do other things within the loop. That's the exact moment when programming clicked for me. My perception of it changed from being a glorified way to write out steps (like a hair-washing algorithm on a shampoo bottle) to realizing it could be very expressive and flexible.