Plug-and-feather refers to a quarrying method used for reducing large chunks of stone to smaller sizes. A hammer drill is used to drill a row of shallow holes along the line where a break is desired. The feathers consist of two iron strips that are flat on one side and curved on the other to fit the wall of the drill hole. They are placed in the hole, and a steel wedge called a plug is placed in between them. The plugs are sledged with a hammer. The sharp, repeated blows generated from the hammer in succession work in combination with the splitting force of the plugs and feathers to rupture the rock.