When digital archaeologist Henry Rothwell was working on graphics for a smartphone application about Stonehenge and the wider landscape, he required imagery for
Bluestonehenge, a prehistoric henge and stone circle monument that was discovered about 1 mile (1.6 km) south-east of the main site. Using an image by archaeological photographer Adam Stanford taken during the excavations on The Stonehenge Riverside Project, Rothwell created a digital circle of stones and overlaid the images.
     In discussion with Stanford, he realised that one stone hole had been missed from the reconstruction, and it quickly became apparent that an oval layout matched the full set of excavated holes far better than a true circle. What is more, the Bluestone Oval fitted exactly in size, shape and orientation with those at Woodhenge and Stonehenge.
     Stonehenge and Woodhenge are famously aligned on the mid-summer and mid-winter solstices. If the new model of Bluestonehenge is correct, it also shares this alignment, adding weight to the hypothesis that Durrington Walls and Stonehenge were connected - three oval shaped monuments sharing a common alignment and connected via the river Avon.
     Rothwell tried another bluestone oval; that of Bedd Arthur, in the Preseli mountains of Wales - very near the source of the bluestones used at Stonehenge. Bedd Arthur is more of an elongated teardrop than an oval, and also displays a much lesser degree of symmetry than any of the other sites mentioned here, however its orientation, size, and the material used in its construction are the same as the Bluestone oval at Stonehenge.

Edited from Past Horizons (6 October 2011)