The left image shows the four nonagons, three of which are shifted from the axis of North-South on 5, 10, and 15 degrees, breaking the circle on 5 degrees.
Now it is easy to calculate the angles between the directions to the main objects of the system, the azimuths of which are wonderfully situated around Sigiriya multiply to5 and 10 degrees.
You can quickly calculate the error, the exact value of the azimuth must end in 0 or 5 degrees.
But during the rotation thenonagon gives some more of the most accurate and original combinations of azimuths.
So, if we rotate nonagon on 0.8 degree counterclockwise we will get the exact directions to Teotihuacan, Lalibela and Great Zimbabwe.
Having turned nonagon on 1 degree, we will get quite exactly directions to Stonehenge and Kailas, the angle between is 40.66 degrees.
Rotation of nonagon on 2.5 degrees clockwise, gives direction to Lhasa, which, as we remember, also determines the orientation of the octagon and the direction to the Great pyramid. The angle between the two lines is 80.5 degrees.