Incredible Staircase Illusion Will Leave You Scratching Your Head

I was hard at work doing some research for an upcoming...OK, I'll stop there with that lie. Everybody knows I don't really work. Anyway, I found this video of a staircase at Rochester Institute of Technology that is pretty wicked. Basically, what we have here is a staircase violating the laws of physics by looping around itself. It's definitely an illusion that will amaze you.

I don't know how real this is. My guess, is that it's just some illusion cooked up with some trick photography. Either that or things that I did in the 80's are catching up to me.

How do you think this illusion was performed?