I began my career as a software developer. I wrote code. I was only responsible for the code that I wrote, not for the complete system and not for the work of others. As I advanced in my career, I became a team leader and then a software development manager. I became responsible for the work of others. That is when I first started to notice the difference in output from different developers. Some developers produced code 10 times or even 100 times as fast as others. I do not mean that they produced 10 times as much code in the same time period. I mean they produced 10 times as much functionality, sometimes with one-tenth as many lines of code. Some people