The diagram illustrates the development of the cutting tool from two different periods, specifically 1.4 million and 0.8 million years ago, within the Stone Age.
Overall, although the two cutting tools feature the characteristic appearance of ancient utensils, it can be seen that the latter design has seen vast improvements in the size, shape, and finishing quality.
Tool A, which is a depiction of a Stone Age cutting tool used approximately 1.4 million years ago, has a height and width of about 7.5 and 3 centimeters, while tool B, referred to as a later part of the Stone Age, is about two-thirds of the aforementioned dimension. Notably, tool A looks to be quite a crude implement, while tool B appears to have been refined into a more effective cutting device.
From the front and rear views, tool B appears to be much wider than tool A and has a rounder body shape. The cutting edges also appear to be more distinct and symmetrical. The side view shows a distinct difference in the thickness of the two tools, with tool B significantly slimmer than tool A.