@grimalkina Since I see Piet and APL have already made the list, let me throw in a suggestion for jq (https://jqlang.github.io/jq/) - but specifically, doing something complex in jq. Like, I've been writing little jq one-liners for ages, but it was only when I wrote a full 100-ish line program in jq that I started to appreciate its stream processing model as being something distinctly different from the typical paradigms (functional, procedural, OOP, async, all that jazz).