Looking again at them, they jogged a memory from about 20 years ago, My wife ran the local Brownies and the Guides branch and she got me to cut out the sides, bottom, tops, fronts and backs so that the girls could assemble with a few tacks and instead of hinges I used inner tube rubber which the girls stapled to the top and back. They were a great hit with the girls as they could take them home to put in the garden and they were proud that they had made them, I think I cut out about 20 sets.
Peter