The diagrams show humans ’ cutting tools 1.4 million years ago and 80,000 years ago.

The diagram below illustrates the refinement of the cutting tools in the Stone Age over 600, 000 years. Over the period shown, tool A, which appeared to be more rudimentary and showcased less superb craftmanship, was upgraded in both practicality and aesthetic thanks to more advanced carving techniques that helped enhance its sharpness and create more intricate patterns. However, there were some similar structural features between the two versions. It is clearly seen that both the cutting instruments, which looked relatively thin from the side view, had a curved head and a pointy tip and were symmetrically shaped, serving similar cutting purposes. Furthermore, they were relatively the same in thickness, and the distances from the centers to the pointed tops were similar, at approximately 5 centimeters. Nevertheless, some modifications concerning the front and back surface of the older version had been made to make it more functional and appealing by the end of the given period. Specifically, with more chiseling effort, the stone tool makers of 0. 8 million years ago made tool B smoother, which translates into sharper edges, thereby, a better-cutting tool. It is also worth noting that tool B bore a striking resemblance to a teardrop when looked at from the front view.