Learn about the Memento design pattern in this 21-minute tutorial video. Discover how to easily store previous states of an object using three main classes: Memento, Originator, and Caretaker. Explore the implementation details, including how the Originator sets and gets values from the current Memento, creates new Mementos, and assigns current values to them. Understand the role of the Caretaker in holding an ArrayList of previous Memento versions for storage and retrieval. Access the provided code to enhance your understanding of this useful design pattern.