QUO VADIS matte painting work

The photo above appears on a British lobby card, which, technically, is a goof because in the final movie, matte paintings were added to show that the arena was much bigger, taller and more crowded. That photo is fascinating because it's basically a real photo of the actual set as it appeared when they filmed the movie (I got the photo from the lobby card at Colossal Quo Vadis). Below are screengrabs of those scenes with the matte work added. To give illusion of an actual live crowd to the static painting, the matte paintings, which are done on glass, were left with empty spots and behind the glass they had objects moving back and forth which gave the illusion of movement in the crowd. Cool stuff.