I didn’t focus on the iterators at all and still didn’t get the point. What I got so far; an architect wrote a book with some definitions that allows people dis

I didn’t focus on the iterators at all and still didn’t get the point. What I got so far; an architect wrote a book with some definitions that allows people discuss a solution. Then the author says we should take that seriously. Which is fine, but how exactly? The author spends a lot of time on explaining why (for his POV) software design patterns are wrong, but no example of how to use what the book says in software. What am I missing?