Check out this video, featuring the unusual "Escherian Stairwell" at the Rochester Institute of Technology:
http://www.youtube.com/watch?v=iBY4HaAngaA

The sources below give you a few more hints about what's really going on (as if anyone here at the Café hasn't figured it out already):
http://www.rit.edu/news/story.php?id=499......wsletter

http://www.kickstarter.com/projects/1123......ern-myth

With a little practice, though, it's not too hard to see how you could make people experience this in real life.

Very amusing. My niece and nephew once wanted to see if they could start a new slang word that meant nothing. They picked the word "pots." At every opportunity with friends and in school they would say things like, "Oh, that's so pots!" and "He's going out with you? Oh pots!" and reply to "What's the matter?" with,"Nothing...pots." They claim there are still students years later at their college who use the word they invented.

Great. Loved it when she runs vack up to chech hes still there

How difficult would it be to build a staircase in movable segments on a rotating set so you can have someone actually make a run upstairs to wind up at the same place, or downstairs? IE each leg of the journey is really either up or down and it's the platforms that move In the case of what's in this video, need the part that's out of sight in the platform shot to serve as elevator.

Yeah, but unless the footage is edited, he's getting from the top of the stairway to the bottom of the other stairway very quickly. I'm thinking pole slide, but it could be an angle/camera perspective thing that I'm not getting.

I'd think the easiest way to present this with any similar stairwell would be with the use of several sets of twins, and maybe a set of triplets. They'd have to practice to get their timing, though.

I'd thought split screen at first, then not. What is it we're not seeing? Obviously it's not possible, but...how? The Kickstarter thing reveals nothing as far as I could see.

At first, I thought it was some type of gigantic periscope effect...

Here are my thoughts now...

First of all, there are two cameras, and there is (simple) video editing involved.

There ARE doubles/twins, but only one or two sets; the "host" and the camera operator. One set above, one set below. This will give the participants (real people) the experience and the honest reactions they see. They run up the stairs, and see (apparently) the same people.

Now, the video - a simple splice between the "bottom" shot and the "top" shot, to see the participants on both staircases.

This is how I would do it anyway.

Wouldn't even really need twins for the cameraman - just identical clothing, since he's holding a camera in front of his face.

I thought that this was interesting until I saw it was a gag, now it is not as interesting.

I was totally sucked in to begin with.