As I cut a tiny piece of wire with sharp pliers, it shot off unexpectedly. I felt that little piece of metal hit my lip and then stick somewhere in my throat!
Scientists have dated sharp-edged flakes of stone found in the fine-grained sediments of a dry riverbed in the Afar region of Ethiopia to between 2.52 and 2.60 million years ago.
An enlarged photo of the cross section cut was then traced with a vector graphics program.The sharp edges, one of which severed the rope, are clearly shown in the illustration.