Ever wonder where plywood comes from? And in such varied shapes and sizes? They farm it, of course! Below, a section of a plywood farm found in Caer Firnas: clearly the sphere and pyramid section, with a few tori thrown in for good measure.
In all seriousness, what would prompt someone to leave such a mess? (The culprit was eight days old as of the date of the photograph, so one may excuse creating the mess on the duchy.) Ghastly manners.