What special effects are they using?
Special effects refers to "fake" stuff -- even if it's in the world (and not post-processing), then we're talking about "fake" explosions, spaceships hanging by nylon thread, make-up to make someone look like they have a scar, etc etc etc.
Here what you see is reality: stacks of paper than have been carved and are now being moved.
Do you mean it's a "special effect" because you thought they were marble statues? The video isn't hiding the fact that they are stacks of paper. We see close-ups lots of times. What you see is exactly what it is. There are no special effects.