A spellchecker used to be a major feat of software engineering (2008)
I read an article where a software engineer was about to go on a long plane flight, so he downloaded a file of all english words and tried to write a spell checker during his flight, with no internet access, just as an exercise.  And when he landed, he had finished, and his algorithm was beautiful, simple, elegant, easy to understand, and never something I'd have come up with in a million years.It was actually a little depressing - it made me realize that some people just have a "something" that I'm not going to get through hard work or whatnot.*edit: ah, found it.  https://norvig.com/spell-correct.html