In 1873, J.F. Glidden invented the barbed wire fence, as we know today. According to his invention, the barbs on the wire fence didn't rotate around the wire itself, providing two-sided rigid thorns.
Ten years later, Edenborn and Griesche invented a barbed wire machine that greatly improved the efficiency of making the wire.
I thank Paul Henderson, whose father was a barbed wire collector, for alerting me to this remarkable invention.
tags: invention, efficiency, problem, evolution, productivity, history