Having found stone tools.
Comparing them to stone tools found other place the shapes are very similar.
I suspect the overall shape of stone tools is dictated by the ergonomics of the hand and it only makes sense to incorporate as many usable functions, like scraper, slicer and drill into one stone instead of carrying three separate ones.
Growing we found many arrowheads and “tools”.
If it has a sharp edge, it’s a scraper. If it has A round then flat surface, it’s a corn grinder. If it’s round and heavy, it’s a hammer.