This is to see what looks like with perspective of two vanishing points, rather than the single point perspective that is used most of the times in computer graphics. One point is far behind the screen, and the other is far below. I toggled between the 2 modes in the video above to see the differences. 

I have the impression that there is much more to be explored with multiple vanishing points, such as 3 or even more, to achieve certain effects in computer generated visuals (A very wild thought: Would it be possible to use perspectives and vanishing points to achieve those very subtle effects as in Renaissance paintings, or Chinese traditional landscape paintings? ). But due to the setup of graphic pipelines commonly used, it is not as straight forward as one draws those merging perspective grid lines with pencils and papers. 

The videos has no sound or music background, which I think is better this way.