come to think of it, what if the corners were fulcrums for huge tree trunk levers, that were suspended by wood cranes above, where you attach ropes a few feet out from the fulcrum that pull the block behind, and also have ropes attached on the end that men 90 degrees around the corner are pulling with the lever advantage of the point those ropes are attached.

Maybe a combo of all these things. The corner lever pulling ropes, also those ropes lined with men to assist that pull, plus the farther along the path, the more 'battering ram' suspension pushing posts are added behind the block. I wish it was easy to do animation of this stuff. lol