No, its not simple, the result is brilliant.
I am taking a risk now of being sent to Mongolia.
But this stunning photo, has inspired me.
This is just my interpretation of the ring formations you all find, please dont answer , or anything, or my flight tickets will be in the post.
When I dowse a series of polygons ( for all the world, circles ), they spin in opposite directions, out from the centre, that is , the first one goes clockwise, the next anticlockwise, and on.
If You have two adjacent polygons ( Avebury ) and you divert the flow ( the lines , shown through the rings ) then you would at a point have an incomplete circle.
I consider by carefully placed stones this could be achieved.
If I could make a request, could you consider, taking a bearing of where you would consider the person carving these was looking.
The above is my thought, nothing else, nothing to get upset about.
K.