I learned a lot about programming by taking this book and, since I didn't own a computer, figuring out how the code could produce the example listing. That's w

I learned a lot about programming by taking this book and, since I didn't own a computer, figuring out how the code could produce the example listing. That's where I learned things like, to swap the values of two variables, you copy one to a third variable temporarily. I learned a ton of patterns like that. Eventually I got my VIC-20, then an Apple ][, then an Amiga.