Memento Pattern:
The Memento design pattern is a behavioral design pattern that provides the ability to restore an object to its previous state (undo via rolling back). It's used when we want to save the state of an object so that we can restore it later.

This pattern is comprised of three main elements:

1. Originator:
This is the object whose state we want to save and restore later. It creates a memento that contains a snapshot of its current internal state.

2. Memento:
It's a plain object that doesn't have any functions, only data. It holds the state of the originator.

3. Caretaker:
The caretaker object controls the memento, but it doesn't modify it. It maintains the history of mementos, and it can restore the originator's state using the memento.

Think of the memento pattern like a game where you can save your progress. Your current game progress is the "Originator". The save game feature is the "Caretaker"; it saves a "Memento" of your game, a snapshot of your current state (game level, score, etc.). You can continue playing the game, but if you make a mistake or lose, you can always load the game from the last saved "Memento", which brings your game back to the state it was in when you last saved.

Implementation in Go: