Funny you would say that, Cb88. I used to do that all the time in the 1980s and 90s. From punching out punch cards on an IBM Punch Card Typewriter to writing assembly code, doing it on paper by hand and then typing up the code. Then run the program through my head to see if it runs logically. Once I'm satisfied with the code, then I compile it and with my programs, its about 95% bug free. 95% bug free is hard to obtain and many programmers would not want to do this and they end up with buggy software. This is just an exercise in logic, which is easy. I do not know why programers don't do this and assume their work is right when most of the time it is not and then spend hours and hours of debugging the software. Running the code in your head and making corrections as needed saves you (the programmer) for hours of debugging headaches.