A hammered finish is an all over decorative treatment used on metal that is created by repeated blows of a small hammer. The results create an all over pattern of miniscule divots that give the piece a warm glow. The technique can also be produced by short bursts from a polishing wheel, on a flex shaft, worked in many directions or a flex shaft reciprocating hammer. Casting and other manufacturing techniques produce a finish intended to imitate a hammered finish but are usually identifiable by their perfectly flat surfaces on each of the "hammered" surfaces. Hammered finishes were particularly popular during the Arts & Crafts period.