Storage for pool. Easy to build, I think the bottom would have more holes for water draining. Maybe staple some sort of screen inside the bottom also to keep small critters out and probably some casters or short legs to keep it off the ground.
This passage way made with the same shipping pallets could be perceived as a dual natured pallet wood creation. This is a decorative measure, and also a protective measure as well as it would prevent us from some tiny harmful worms and bugs that might cause irritation and inflammation. And the wooden planter is even better than that.