Anthony Johnson has kindly made his and Alberto Pimpinelli's paper on laying out a 56 sided polygon using just pegs and ropes available on Academia.org. Of course this isa proposed solution to the the laying out of the Aubrey Holes.
"A recent computer-aided-design investigation of the Neolithic 56 Aubrey Hole circuit at Stonehenge has led to the discovery of an astonishingly simple geometrical construction for drawing an approximately regular 56-sided polygon, feasible with a compass and straightedge. In the present work, we prove analytically that the aforementioned construction yields as a byproduct, an extremely accurate method for approximating a regular heptagon, and we quantify the accuracy that prehistoric surveyors may have ideally attained using simple pegs and ropes. We compare this method with previous approximations, and argue that it is likely to be at the same time the simplest and most accurate. Implications of our findings are discussed."
They even bring in Plutarch's Moralia. Isis and Osiris "It is plain that the adherents of Pythagoras hold Typhon to be a daemonic power; for they say that he was born in an even factor of fifty-six; and the dominion of the triangle belongs to Hades, Dionysus, and Ares, that of the quadrilateral to Rhea, Aphroditê, Demeter, Hestia, and Hera, that of the dodecagon to Zeus,c and that of a polygon of fifty-six sides to Typhon, as Eudoxus has recorded."