Since TeX and LLVM were already mentioned, I will casually mention the comments in Laravel's codebase which are all three lines long with each line exactly three characters shorter than the previous line. The art of computer programming at work.
Honestly...neurotic and counterproductive. You have to add too much useless words to make it fit. Most of these comments could be much shorter and easier to read. Also too much separators and whitespace around those comments.
Opinions differ. I personally like it, but I don't think I would manage do it in a reasonable large codebase. Still, I agree with the points brought up in the Reddit discussion on the topic (https://www.reddit.com/r/laravel/comments/20ovey/just_notice...), in particluar:
I think it's awesome and I'm trying to do this too. It is a great trick that forces you
to re-read your comments and be as clear as you can. Also, you take the time to find
synonyms and look for typos. Overall it's a great way to learn how to be thorough.
Example (config file, but the entire codebase is like that): https://imgur.com/UnIUZmZ