"The economic scenario that we come across on reaching Stage IV of the civilization in the Sarasvati Valley, in the 3rd millennium BCE, may well be termed as a revolution within an evolution. There is no walk of life in which this revolution is not reflected—whether it be town planning or industrial advancement, or trade. In this stage, there sprang up a regular system of writing, weights and measures, and seals and sealings, along with the production of pieces of art and craft—indeed, all that is needed to call it a highly advanced civilization, as against its humble beginnings—pit dwellings in the 5th millennium BCE."