Yes, I was one of those people who had initially thought maybe it was real at first in some wacky optical illusionary way.
Then I realized they offered no explanation whatsoever on how the illusion worked.
It never dawned on me that wacky optical illusions as a general rule are NOT included in the blueprints of any public building. Perhaps for good reason.
My brother-in-law designs homes and had my wife and I go to a conference with him were Rafael Nelson M. Aboganda was one of the speakers. It's too bad hardly anyone has heard of him because he was a really amazing guy. Aboganda mentioned the stairwell in his speech but during the question and answer period he just laughed and refused to say it worked.
This is episode three of Can You Imagine. The Microsystems Engineering episode was kind of dry but had some cool images of nano machines working under an electron microscope.