We can explain a simple process step by step but a complex system is better addressed part by part. Object-oriented programming introduced this shift into programming allowing for the creation of much more capable systems by those who had made the transition.
Examples
Alexander sought out the patterns that made a town work. A town is of course a system that works well or doesn't. We modeled object-oriented programming guidance as patterns following the examples Alexander used for towns. The more we learned of his work, the more we understood the challenges before us.