Concentric castle

So imagine you are building a castle with Lego blocks. A concentric castle is like building a castle that has lots of walls protecting it.

The first wall is like the outer wall of the castle. It goes all the way around the castle and has a gate where people can go in and out.

But instead of stopping there and having just one layer of protection, we build another wall inside the first wall. This is the second wall and it is closer to the center of the castle.

Inside the second wall, we build another wall! This is called the third wall and it is even closer to the middle of the castle.

So now the castle is protected by three walls, one inside the other. If an enemy tries to attack the castle, they have to get through three walls before they can hurt the people inside!

It's like putting on three jackets before going outside on a cold day. You have the first jacket to keep you warm, but if it's really cold, you add another jacket, and then another, until you're super protected from the cold.

That's what a concentric castle is like - it's like having lots of layers of protection to keep everyone inside safe.