From the link below:

And this is — as I said, this is the finest you can do. I said, “Let’s do it differently. We don’t have to go 30 feet.” They said, “Sir, if you don’t do 30 feet, it won’t be the same, because of the climb.”

We actually built prototypes and we have, I guess you could say, world-class mountain climbers. We got climbers. We had 20 mountain climbers. That’s all they do; they love to climb mountains. They can have it. Me, I don’t want to climb mountains. But they’re very good. And some of them were champions. And we gave them different prototypes of walls, and this was the one that was hardest to climb.

And we’ve all seen the pictures of young people climbing walls with drugs on their back — a lot of drugs. I mean, they’re unbelievable climbers. This wall can’t be climbed. This is very, very hard.

And what the panel does on top, as I said, is structural, but it’s also very hard to get by panel. Plus, it’s designed to absorb heat, so it’s extremely hot. The wall is — you won’t be able to touch it. You can — you can fry an egg on that wall. It’s very, very hot.

So if they’re going to climb it, they’re going to have bring hoses and waters — water. And we don’t’ know where they’re going to hook it up, because there’s not a lot of water out here. So it’s a very, very hard thing to climb.