What are nested structures?

A nested structure is like a set of Russian nesting dolls, where one thing sits safely inside another thing.

Imagine you have a big toy box. Inside that box, you might find a smaller lunchbox. Inside the lunchbox, you find a tiny jewelry box. This is nesting. The big box holds the medium one, and the medium one holds the small one. Each layer adds a new level of organization.

We use these structures to keep things tidy and easy to find. Think about your closet. You have a wardrobe (big), inside are hanging rods (medium), and on those rods are hangers with clothes (small). If everything was just dumped on the floor, it would be a messy pile. By putting things inside other things, we create order.

Just like a house contains rooms, and rooms contain furniture, nested structures help us organize the world around us. It is not magic; it is simply putting one container inside another to save space and keep things safe.