> APL is another example of dense languages that (some) people like to work in.

I recently learn an array programming language called Uiua[0] and it was fun to solve problems in it (I used the advent of code's ones). Some tree operation was a bit of a pain, but you can get very concise code. And after a bit, you can recognize the symbols very easily (and the editor support was good in Emacs).

[0]: https://www.uiua.org/