Chuck Jones reckons that Disney got the idea from Warner Brothers cartoons. I included a similar shot in a recent production, panning down a broken ladder to a figure at the base, figure 3. The point is that you don’t see the whole background at any one time, only part of it.
It is all very well describing these paintings, but how do you draw them? Not everyone has a large cylinder of glass handy. The key to understanding is to note that what were straight lines in reality become curved lines in the picture. But not just any old curve, they all have the property of being segments of mathematical sine curves. To explain precisely why this happens would be long and tedious. Suffice it to say that in a picture such as View of a Room the projections of the uprights towards the artist’s eye hit the imaginary glass cylinder and remain upright and straight. Whereas the projection of any other line in the scene in this way hits the glass cylinder at an angle, (different angles for different points on the line), resulting in a sine curve when the cylinder is rolled out flat.