I don't know about complex pieces of software. But many algorithms were invented on paper first (or whiteboards.) Conway's game of life became popular before computers were programmed to do it, and people executed the moves with pencil on graph paper. Turing had a chess playing algorithm which he executed by hand on paper.
I've written short sections of code on a notebook before implementing it into a computer. It's slower, but it's possible, and I don't think paper is that inferior to a text editor. It will definitely require a lot more debugging when you finally implement it on a computer. So maybe write lots of test cases.
This I can see, but the parent seems to be talking about commercially viable software. I think people should be careful when discussing imprisonment as some kind of distraction-free vacation for intellectual pursuits, the reality is that a large amount of time would be spent caring for your mental wellbeing.
Well, most of the people I knew in prison used weight-lifting, tennis, jogging, arts and crafts, instrument playing, card games, reading, cooking, TV watching, naptime, and even alcohol to manage the mental wellbeing.
What can really be tough is if you have someone on the outside you care about who is struggling with their own issues. That, more than anything, puts an imprisoned man into depression.
I've written short sections of code on a notebook before implementing it into a computer. It's slower, but it's possible, and I don't think paper is that inferior to a text editor. It will definitely require a lot more debugging when you finally implement it on a computer. So maybe write lots of test cases.