wall-mounted see-saw bookshelf in solid, local, sustainable oakProject by Tim GermainYear: 2006Cost: £2,500this wall-mounted version features the same marble run in the shelf front edge- when activated by adding/removing a book, the shelf tips and the marbles scurry into actionthe central pivot brackets are made of steel and 6 screws into the masonry ensure the strength of the shelves…… with pins affixed to the wall to limit the shelf’s tip to a couple of inches.