I just realised that when I said this idea just popped into my head, that was not true in the slightest.
It was actually inspired by this leafy necklace. I found it a couple of years ago, a $5 bargain at a Portmans clearance shop, and it tends to attract comments when I wear it (more than any other piece of jewellery I own - most of them attract no comment, generally.)
I realised as I took this photo, that there is a jump ring missing! Will have to fix that.
I remember at some point writing an idea in my notebook for a version of this with felted leaves. I never pursued that, though I may one day. But it was clearly a stepping stone to the crocheted circles necklace.