My assumption is that these statues represent the Buddha followed by the first monks. There is a large amount of symbolism associated with the various poses of the Buddha and I cannot find anything that mentions this kind of line, although it must be fairly common as I have seen several iterations of it.
Photography there is challenging only because the sun vaults high overhead in what seems to be minutes and going back to somewhere for better light is difficult. We did meet a French photographer, travelling with his publisher, who spends 2-3 months in each area and returns multiple times for each book.
This was taken with a Nikon 24-70 at 70 mm f 4
And, thanks for comment.