each square weighs 1 (so each is 1%). the sheet runs −+−+ as a chessboard: the 50 + squares carry a nail, the vertical stroke of the +, poking out top and bottom. gold adds 10^−79.01 per atom until the tips sink to 0.93; then silver unlocks at 10^−47.01 per atom. the sliders run in powers of ten of atoms. the bed is as stiff as the sheet (another 100 pushes the tips flush), so 0.93 means 7 units of metal. ground PEWTER.