Drawing the Sri Yantra
When we begin to study the Sri Yantra, one of the first things that we notice is that the largest of the triangles appears to be ~52 degrees, just like the base angles of the Great Pyramid. We see the triangle used in the DC map layout and many cathedral elevations as well. Patrick Flanagan suggests that the 51'51" triangle is proper for the Sri Yantra, and uses a geometric exercise to generate one.
Here I am going to show how to derive the template that is used for the lodge floor, cathedral plans etc., then I am going to show how the Sri Yantra derives from that template. We begin with a cross and a circle. We inscribe these in a square giving us four small squares. Vesicas help bisect these squares horizontally and vertically, producing a grid of sixteen squares. [The vesica points to 30 degrees from the equator horizontally and the axis vertically.]
Diagonals of our original square mark 45 degrees on the circle, denoting the location of the corners of an inscribed square. The circle that inscribes in this square crosses the corners of the 30-30 square. Where this circle crosses the vesica circles locates the inner most lines - that is, the base of the 51-51 triangles. [If you consider the compasses and square as an equilateral triangle and half a square with the point down and inscribe them in the same circle, where they cross also locates this base line.]
Here we begin with the template and work in from the largest triangles. Notice how the large circle touches six corners; the next circle touches eight corners.
In this image we center circles on the circumference of the original circle, and draw them the size of the inner circle. These locate the next set of horizontal lines.
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