Don't see this kind of barb wire very often. I came across it while thrashing through brush to reach Cherry Creek. It's a strip of galvanized sheet metal with sheet metal barbs that clip on rather than two twisted wires with wire barbs wrapped around at intervals. Some research indicates this type of barbed wire was patented by Jakob Brinkerhoff in 1879. The more conventional style barbed wire was developed in the early 1870s and patented in 1874.