[jjk7]

Yeah it's hard to believe this was done intentionally before the existence of stone tools... did they bite the notches?

[kragen]

Stone tools predate this carpentry by 2.9 million years, so people had been using stone tools for six times as long as of that time, as the time that separates them and us: https://en.wikipedia.org/wiki/Stone_tool#Pre-Mode_I