Round up at least 5 feet of Type M ¾-inch copper tubing, seven eye screws, five No. 6 1-inch machine screws and nuts, nylon twine, and 1 x 6 lumber. Center a 4½-inch-diameter circle in a ...

It’s not news that Leonardo DaVinci was somewhat ahead of his time, and over the centuries many of the creations in his sketchbooks have been created and proved quite functional. The guys from the ...