These shapes are all out of someone's mind. That's important to see. The steel? Hell, even the steel is out of someone's mind. There's no steel in nature. Anyone from the Bronze Age could have told you that. All nature has is a potential for steel. There's nothing else there. But what's "potential"? That's also in someone's mind!
Ch. 8 - Zen and the Art of Motorcycle Maintenance (1974)