A teacher of mine once had a large (10" x 10" x 10") cubical block of wood with a notch -- four inches long and spanning its width -- cut into the top it. A hole had been drilled from the inside of...
A teacher of mine once had a large block of wood out of which had been cut a 4 inch notch. On one side of the notch a hole was drilled. Through that hole passed a long bolt, the top of which was on...