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Think of a box. When you put your favorite toy inside the box, the toy is in the box. It means the toy is surrounded by the box on all sides. The box is like a little home for your toy, keeping it safe and cozy.
Imagine you are wearing a jacket. When you zip up the jacket, you are in the jacket. The jacket wraps around you, keeping you warm and snug. It’s like a hug from your clothes!
Picture a fish swimming in a bowl of water. The fish is in the water. It moves around and plays, but the water is all around it, helping it to swim and breathe.
Think about a cookie inside a jar. When the cookie is in the jar, it stays fresh and tasty because the jar keeps it safe from the air outside. The jar is like a little house for the cookie, just like the box is for your toy.

When you are in a room, the walls, floor, and ceiling are all around you. The room is like a big box, and you are inside it, just like the toy in the box or the fish in the water.