By "borderline impossible" they mean at the end they needed to be able to describe it using a bunch of opposing adjectives and I guess thats kindof difficult but I think its generally accepted that in the world of PR you can now get away with whatever adjectives you want so I guess contradictory ones aren't that hard anymore.

"At the top of this system we needed something completely unique and borderline impossible, typographically. Somehow it had to be this contradiction, that was forever dynamic and new and somehow felt eternal and had always been there; that it somehow felt English, but also transcended that and became universal."