Magicians and filmmakers know that when we look at a photo or an image, unless there is stark evidence to the contrary, we as viewers assume that the top is up and the bottom is down.
Filmmakers often throw their images off balance for dramatic effect. By making the bottom not quite down and the top not quite up, a cinematic environment will be perceived as off-balance and helter skelter. These dutch, or canted, or oblique, or “Chinese” angles can create tension, and separate a particular setting from the rest of the movie’s world.
Photographers take advantage of this assumption in our perception to create witty optical illusions.
But in 2010’s “Inception,” director Christopher Nolan created a dream reality in which spacial orientation was subjective, in which gravity was adjustable. When the dreamer is thrown off balance, when the dreamer’s world is turned upside down, so is the world of the dream.
Nolan created these effects by building a rotating set. The camera retains a fixed perspective on the set, often rotating in sync with it. So to our eyes, it appears that characters bound from floor to wall to ceiling, that gravity itself is shifted.
Nolan was not the first to take advantage of the naivety of our perception. Here’s a little film I put together giving some of the history of a very special special effect.
For a behind the scenes look at the rotating set effect from "Inception," watch here.
ADDENDUM: Turns out that the "upside down cake" effect can be traced back as far as 1902 and Georges Melies.
And 1907, from film pioneer and Melies imitator Segundo De Chomon -
And even earlier, in 1899, from British cinema pioneer R.W. Paul, "Upside Down."
ADDENDUM 2: Independent of any attempt to deceive through disorientation, look at how simple reorientation can create an unsettling effect in this credit sequence from “Devil.”