I remember reading about this ... it was immediately following the first hurled ashtray.
You have to wonder about this first guy. He has a word vocabulary of probagbly twelve words, and has looking at this fancy rock for several days. Then he figures out how to tie the rock onto the spear. A day later, he’s made one for each of the ten guys in the village. Then they all go out and start hunting big-game, and take on some pretty tough creatures.