Vintage Napier 3D Goldtone Cube Runway Statement Couture Necklace

I have never seen this 3-D cube necklace with three different 3 dimensional cubes in all my 67 years. I don’t know if they made any more than one or if it was a one-of-a-kind? I have seen a single one on a chain, but never three. I’m having such a hard time listing this because it’s so incredible! Beautiful goldtone in the three dimension is just stunning! There is some slight gold loss on the backside which you can see in picture #3 on the corners, but do not see any from the front. Signed Napier on all three pieces and also on the clasp. I believe it to be from 60’s? It measures approximately 20 inches and also has a 2 inch extender so it would hang 22 inches if need be. Definitely breathtaking and a real show stopper!