The Eric Doeringer Signature Stamp is a commercially-made rubber stamp bearing my signature (it comes packaged in the green box pictured above). It is an extension of ideas found in the readymades of Marcel Duchamp and the found imagery of Andy Warhol.
The artist's signature is the mark of authenticity on a work of art. By stamping my signature on any item, it is transformed into a piece of art (it may not be good art, but it is art nonetheless). Thus the owner of the signature stamp can create an unlimited amount of artwork "by" Eric Doeringer. This upsets ideas of authorship, originality, and the commodity value of art.