Tumbles, leaps, spins, glides, somersaults, headstands, backflips, and balletic pirouettes -- they are all in there, together with contortions one has no words for. Truly impressive....
Anyway, let's be serious here. First things first. I am actually quite impressed by Chapter 4 of Vol 1 of "Stonehenge for the Ancestors" by Mike Parker Pearson and Colin Richards. I don't often say this, but please read it -- for free, if you cannot afford the real thing. As a chapter it is well organized, clearly laid out and nicely illustrated. It's the best summary of the "bluestone situation" on Salisbury Plain for 25 years, and stands alongside "Stonehenge in its landscape" (1995) by Ros Cleal and others, and the big studies published by Richard Thorpe and OU colleagues (including Olwen Williams-Thorpe and Rob Ixer) in 1991.https://www.sidestone.com/books/stonehenge-for-the-ancestors-part-1
All that having been said, the most impressive thing about the chapter is the extraordinary mental gymnastics involved in avoiding a perfectly obvious conclusion -- namely that the bluestones were all on Salisbury Plain -- or maybe very close at hand -- at the time when Stonehenge was conceived and created. In the abundant evidence relating to the 43 bluestone monoliths, the pits that might have held them, and the widespread occurrence of related lithics or fragments in hundreds of different locations, there is nothing at all that suggests that they were transported from Wales by human beings and "delivered" to the Stonehenge area some time around 5,000 years ago or maybe in several phases after that date. If you want to argue that, you have to do mental gymnastics just like those performed by Parker Pearson and Richards in this chapter.
It is perfectly obvious from the multiple bluestone rock types, their shapes, their weathering crusts and faceted surfaces that they are glacial erratics -- most of which were used just as soon as people started to get interested in making arrangements of stones. This is what the stratigraphy shows. The bluestones were used as found, and some were later split and fashioned into pillars and lintels. Some were then suitable for use in the bluestone horseshoe in one of the later phases of stone setting. The occurrence of the stones in the Stonehenge area may be the simplest and most logical answer to the question: why is Stonehenge here rather than somewhere else?
I predict that over the coming years more bluestone lithics (some of them quite surprising) will be found, in more locations; that progress will be made in identifying heavily degraded glacial deposits on Salisbury Plain; and that more hollows will be found that might have contained bluestones precisely where they were left during a phase of glacier ice wastage.
I cannot see the slightest reason why anybody should need a more complicated or wonderful story than that.