At the next level down in size, the mortar extending from the wall has been sculptured with implausibly exquisite precision. This scanned-in image from the print edition of the Washington Post shows it in better detail:

Washington Post, May 29, 2002

Consider what would be involved in building a wall of rough, rounded stones with mortar like that. A lot of mortar would have to be left extruded as the stones were laid. Then, just before the mortar hardened, it would be necessary to go back and carve it rapidly into that neat, rectangular lattice. Labor to do that might be cheap in that part of the world, but is mortar?

Finally, at the smallest size scale, look at this one stone that stands out because it has three sharp edges:

It seems to have been embedded in a mortar-like material. But that material is visually indistinguishable from the "stones" of the rest of the wall!