This is the plan of our extrapolation of the markings as discovered by Anthony Murphy and Ken Williams at Bru na Boinne.
It shows timber post-holes in a double collonade externally, with what are described as a segmented double fosse internally. No excavation has taken place to date to determine what this unique fosse arrangement might mean. The presumption is that these indications are fosse holes and not pits for standing stones, as there is no typology in Ireland of such a structure.
We are showing a multitude of people in the space enclosed by the monument, to indicate scale. The alignment of the portal structure is supposed currently to be Lughnasa and the shadows in this image are at sunset at that time.
For more from the experts themselves listen to the podcasts at https://www.mythicalireland.com/MI/blog/videos-and-films/three-podcast-interviews-with-anthony-murphy/