perhaps thats what he did - remember we're really giving the idea loads of thought, but we're at the other end of the evolutionary scale and we've seen so many commonplace feats of engineering that we can conceive of immensley technical practicalities easily. Your average Stone age chappy would be at the bleeding edge of simple mechanics in his day, he wouldnt be on the shoulders of giants as we are, but faced with the practicality of inventing engineering from scratch! Look at a kid building stuff with Lego, they dont understand how to build a wall with a flemish bond so it doesnt topple, they take the shortest route to the biggest model - surely S.A.M would do the same (at least with the early monuments) ? Maybe we cant see the monument for the megaliths?