@k11m1 LOL...

It is not impossible, but it takes a lot of concentration, and hopefully a smaller programme to work with.

When I first learned, we did not have access to computers directly at all; that was reserved for the high priesthood, serving the needs and whims of the large, school gym sized computer center. We students would create our programmes, that had to do some task assigned by profs.

And later get the lines of code ready for input -- punch cars for us. I did my own punching, found a quiet room wth a machine in the Physics department, little used, and would go there to prepare my deck,

Because testing was laborious (revisions equaling new cards needed, finding a punch, etc) we tried the best we could to read and follow the logic.

But I think getting it bug free in 3 passes was good, very good.

Fast forward many years, and me teaching basic programming; my students were bright, did well, but they found it quite hard to create a small programme in paper only (without trying to run and see what happens, to find the errors).

This was good for discipline, but it is less common. They whined everytime I called for a pencil and paper only task, lol.... 😺