In this image the lines between the large blocks that were used for the exterior walls of the Ara Pacis can be seen. To judge from the way in which the carving of the figure crosses these divisions most, if not all, of the detailed figure carving was completed once the blocks had been installed. Half way down the section of relief shown in this image a block line can be seen running straight through a figure and it would have been nearly impossible to carve this individual before these two blocks were fitted closely together. When two blocks are fitted tightly together it is very easy for a skilled carver to work carefully across their join but it is very hard to carve detailed ornament on two blocks separately and then fit them together.
Also visible in this image are several patches of darker coloration left to show the colour that the surface of the stone had been before restoration commenced.