At that age I couldn't wrap my head around *any* shoelace knot. I gave up around 9 or 10, then tried again at 15 and that time it clicked.

I'll bear the flat-vs-round thing in mind, thanks. Not that it's going to matter if I can't figure out a way to remove the current shoelaces: they've been stuck the entire time I've owned them. I'm not sure what went wrong during their time with the previous owner: road-salt impregnation, maybe? I found the reef-knot article while searching for advice on this, but couldn't find anything relevant to my actual question.