the stones where chipped into squares, then they were motared together.
they were as strong as brick or stronger depending upon the stone used.
they jut took such a long time to build because you would have to chip every stone intasquare like shape, then one would have to mix the lime/or cement-like substance with water, before using it.
i figure for them to be realisticaly apllicable it would take 20% energy per cut block.
and that all parts of the wall would take the same amount of brick.
for the gates i was thinking of a large wooden door.

the great wall of china was made of stone, not wimpy little bricks.
please give extended feedback