A hollow clay ball of spherical, ovoid, or oblong shape holding tokens and usually bearing seal impressions. Clay envelopes, dating from 3500 BC, have markings corresponding to the clay shapes inside. Moreover, these markings are more or less similar to the shapes drawn on clay tablets that date back to about 3100 BC. These markings are thought to constitute a logographic form of writing consisting of some 1,200 different characters representing numerals, names, and such material objects as cloth and cow. Tokens placed in an envelope might have constituted a sort of bill of lading or a record of indebtedness. To serve as a reminder of the contents of the envelope so that every reader would not need to break open the envelope to read the contents corresponding shapes were impressed upon the envelope. But if the content was marked on the envelope there was no need to put the tokens in an envelope at all; the envelope could be flattened into a convenient surface and the shapes impressed on it. Now that there was no need for the tokens at all their message was simply inscribed into the clay. These shapes drawn in the wet clay with a reed stylus or pointed stick constituted the first writing.