There's an insightful story that's used to explain lateral thinking, or thinking "outside the box". It goes like this:
A truck driver tried to pass under a low bridge, but the truck was too tall and got stuck. Traffic piled up behind it, and soon emergency workers, engineers, firefighters, and other truck drivers gathered to try to help.
Each one thought of possible solutions based on their own field of expertise. Mechanics thought of dismantling the truck piece by piece. Engineers thought of chipping away at the bridge. But none of the solutions were feasible. Then a boy who knew nothing of mechanics or engineering came along...
How would you solve the problem? Pitch a potential solution. Then your teacher will tell you the rest of the story and how the problem was eventually solved.
The end of the story:
"As they were arguing over what to do, a boy walked by, stopped, and said, "Why don't you just let the air out of the tires?" A simple idea that none of the experts had come up with. So they let some of the air out of the tires and the truck was able to drive free."