Nad wrote:

> I find it also a bit unclear what John means with "you have reached all its predecessors" By that he probably doesn't mean "had been at all predecessors states" but more "performed all predecessors tasks"...

That's not really what I meant, but it's what I _should have_ meant. One reason is that [Jared Summers, an official expert on PERT charts](https://forum.azimuthproject.org/discussion/comment/17819/#Comment_17819), answered my puzzles in the way that's consistent with this correction.