Early humans used stone flakes as tools, but it took them at least a million years to improve the design. (newscientist.com)
A flint - knapper makes sharp stone flakes by striking a flint «core» with a hammerstone. (npr.org)
Capuchins make stone flakes that could be mistaken for hominin tools, but they do so by accident in search of mineral dust they lick, perhaps as a medication (newscientist.com)