'To test the theory, researchers from the University of Exeter constructed a model in which wooden balls were inserted into grooves dug out of timber planks.
When heavy concrete slabs were placed on a platform above the balls, held in position by more grooved tracks, they could be moved with ease'.
The precision needed to do this with the tools available at the time makes a nonsense of the whole idea. I have been a qualified carpenter/joiner for 45 years and if anyone thinks they can chop down trees and make beautifully precise planks with precision grooves in with just a stone axe then they need to wake up to reality. Using stone on stone we have seen how precise man can be, but not on green or seasoned wood...not a chance! Maybe the archaeo should gives us a demo of his woodworking skills (g)
By the way, I agree that it's an unrealistic thing for the people of the time, and with their tools, to achieve that has been described, but it's a pretty good modern solution to the problem in very basic engineering terms. I'm a design engineer, and I think working wood into balls that fitted into fairly accurate wooden grooves like that would have been impossible back then in my humble opinion. Your 45 years of experience as a professional in that field seals it for me. It's an interesting subject, though.
Cheers,
TE.