I have noticed every page I scroll causes a comprehensive loss of around 90%, so in reading something that is 10 pagefuls long, I might only be able to produce a tiny part of the program.
Your milage may vary.
I find not scrolling, and just moving my eyes, I rapidly absorb the program, and I find most bugs just by reading the code. This practice is absolutely impossible for me if I have to scroll very far and made difficult by scrolling at all.
I do not know how to do this except to write horizontally.
Some members of that community prefer this style because they find it more readable.
As a side project I implemented a small text editor in this style. I had a working text editor with the ability to load a file, insert and delete text, scroll around a large file, and save changes. It fit within about 100 lines of concise (but I wouldn't say obfuscated) C.
In the end I decided to reformat it and use my usual style before implementing more features. But it was a good experiment and I now understand the appeal of the ultra-condensed style you see in J, K, some Forth, and some Perl code.