HELP!!!!!!! Whats the New York Soloman R. Guggenheim Museum Font????????????????

Hey does anyone no what font has been used on the sign on the outside of the New York Guggenheim designed by Frank Lloyd Wright?


Here is a pretty average photo of it!

Here is a good picture

My educated guess is that this is not a font, but Lettering designed by the architect or someone else. Not all letters come from a font.

If you want something similar, here are a few:

Viktors Raven