Programming without a computer
This is called Mathematics, we've been doing it for 2000 years already, long before computers, and got pretty good at it :)
https://en.wikipedia.org/wiki/Curry%E2%80%93Howard_correspondenceThe Curry Howard correspondence is an equivalence between programming (specially functional programming) and proving theorems. This is not only a theoretical one, but proof assistants (a program to formally verify theorems) actually use it! LEAN started as a proof assistant (and was very slow) and now it is also a general purpose functional programming language. They even use it to program robots
https://galois.com/blog/2021/03/real-time-robotics-control-in-the-lean-language/