To see that the paper is two-dimensional geometric circle when stacked several sheets of the picture, we can see three-dimensional mathematical legs are cylindrical.
To see how a piece of a pie shaped two-dimensional geometry to bring as many as number of nested panels are seen as alarming as we stand three dimensional cylindrical shape.
You can see that the paper shows two-dimensional geometric forms a circle when the number of multiple overlapping images will be seen as the figure we stand three-dimensional geometrical motifs as the cylinder rise