The diagrams illustrate how Stone Age cutting tools developed between 1.4 million and 0.8 million years ago, with each tool shown from the front, side and back.
Overall, the latter tool is noticeably larger and far more symmetrical, with smoother faces and a thinner, sharper profile than the earlier one.
At 1.4 million years ago, Tool A had an uneven outline and a relatively crude finish. From the front and back views, its surfaces appear irregular, with a broad middle section and poorly defined edges. The side view also suggests a comparatively thick body, indicating that the cutting edge was less refined.
By 0.8 million years ago, Tool B had a more teardrop-shaped form, featuring a pointed tip and a rounded base. Both faces are more evenly flaked, creating straighter, more consistent edges. In addition, the side view shows a slimmer, blade-like cross-section, implying a sharper cutting edge compared with Tool A.