The metal surface used as support for impressing marks and signs, quite similar to the rocks signed by prehistoric forefathers in the past. In this way the matter keeps a real linguistic code through human intervention. Decorations were represented in a stylised and conventional way also during Neolithic age, so they were considered as simply geometrical motif. So the triangle symbolized life; the lozenge symbolized seeds in a field; the pillar (line) was life-force power and the circle was sun.