Thanks G.
I'm a dunce when it comes to anything mathematical. I've really tried to get into astroarchaeology but it just refuses to penetrate my skull.
The closest I've come to it is Ron & Margaret Curtis explaining things to me. I guess it's a different game when your being dragged around a beautiful monument like Callanish by a wonderful, inspirational mad woman.
Margaret and Ron even got my head around the geometry of circles by sitting me down and making me play with some string and sticks in her megalithic sandbox.
I reckon when it comes to things astro, the sandbox is just about my level.