Construction of the regular heptagon using a grid

The secret of drawing the regular seven sided pentagon with compass and straight-edge is something which, as Blavatsky noted, has not yet been revealed to mankind. Nevertheless, several ingenious methods have been derived which give extremely close approximations which are sufficiently close for practical purposes. This thread at the Henry Lincoln discussion forum contains several examples.

The above diagram shows how the regular heptagon may be easily constructed using a grid of squares. A circle is struck with radius (4,2) from a chosen grid-point as centre. If the top of the circle is the first of 7 points, the third and sixth, counting clockwise or counter-clockwise, may be found where the circle is cut by the first horizontal below the circle centre-line. The remaining points may then be obtained using compass.

Related Pages:

The four keys which unlock the relationship between the Rennes geometry, the map and the landscape

The Method: How to draw the 1:25 000 scale map geometry, with basic tools, in Ten Figures

The Eighteen Royal Cubits: The Giza/ Rennes connection

Hidden Geometry in Art:
Pierro Della Francesca:
Fra Angelico 
Fra Luca Pacioli
Denderah Zodiac

Geometrical Analysis of the East Meon Crop Circle