The diagram illustrates how cutting tools in the Stone Age evolved over 0.6 million years. Overall, it is evident at first glance that the sharpness of the edges have increased while the outline of the cutting tool has changed.
To begin, 1.4 million years ago the cutting tool was roughly pyramidal in shape when seen from the front, and the rear view was almost similar as well. In contrast, the same tool after 0.6 million years later appears more flattened, wider with a pointed end and polished surface. Additionally, the tool doesn’t have the same front and back appearance. In terms of similarities the length of the tool hasn’t changed and remains at approximately 10cm.
Looking at the side view, the edges of the tool have sharpened and acquired more uniformity over the period. With the length constant, the thickness of the tool reduced to one quarter of the breadth it had 1.4 million years back.