What runs around a yard without moving?

How to think about it

1. Running without moving tells you the word “runs” means “extends” or “goes along”, as in “the road runs north”.
2. What goes all the way around the edge of a yard?
3. The hint mentions keeping a dog in, which points to the boundary itself.
4. A fence runs around the yard and stays planted in the ground.

Why “a fence” is the answer

A fence runs around the perimeter of a yard, meaning it extends along the edge, and it never moves. The riddle borrows the sense of “run” that we use for roads, rivers and lines on a page. Hedges and walls follow the same idea, which is why they are reasonable guesses.

Common wrong answers

• A dog. A dog runs around the yard, but it certainly moves while doing it.
• A sprinkler. A sprinkler may turn, but it does not run around the whole yard.