https://neetcode.io/courses/design-patterns/0

Design patterns are a way to solve commonly occurring problems in software engineering. They are reusable, tested solutions to certain software design problems. They are not cookie-cutter solutions, and developers using them can tailor them to address the specific problem at hand.  Let's start with a brief overview of the four pillars of object-oriented programming - abstraction, polymorphism, inheritance, and encapsulation (a.k.a. A-P-I-E).  Abstraction - It's about capturing the essence of real-world entities by focusing on their crucial characteristics. Abstraction helps in managing complexity and ensuring a clean design.  Polymorphism - This is the ability of objects to assume various forms and behaviors. It’s the essence of flexibility in OOP and leads us towards certain design principles we’ll touch on shortly.  Inheritance - A mechanism where one class inherits attributes and behaviors from another, fostering code reusability.