Art or Architecture?

On the beach near Fort Popham, Richard and I found a series of structures constructed with washed up wood. They were all shapes and sizes, and progressed quite far down the beach. This is one of them. We couldn't really imagine who would have built these. If there had been one or two it is easy to think some young kids got industrious but I'm not sure they'd have had the perseverence to build so many. Maybe a Boy Scout troop project? Any other ideas? It was fun to walk down the beach and see them all.