If I had to guess, the principle would be the same as a keystone in an arch. Except the logs are likely notched into the center as well.
Discussion
Oh wow, I didnβt even think of that, it totally can be based on keystone principles ππ»
yes, I see it now, and the more "spokes" / beams, there are the less gravity pressure on the walls. I'd like to see them dropping that center piece into place during the building. that must have been interesting.
#smij #zapd