In The Upwelling, specifically in one of the images of *the lower left hand portion* of the regular septagon in the New Jersey pine barrens or a similar image of the regular septagon that encircles the village on/near "the Mountain" (at least in the Amazon Kindle ebook version -- I assume it's the same in the print version), the image contains a "120" degree label in the lower left hand corner, inside the septagon, which is an internal angle for a regular hexagon not a regular septagon.

The general formula for the internal angles of an regular n-gon is : θ = 180 - 360/n , where n is the number of sides (or, if you prefer radians, θ = π - 2π/n). If the angle is 120 degrees ( θ ), then we have : n = 360/(180 - θ) = 6 sides.

The internal angles of a regular septagon are : 128 + 4/7 or approx. 128.57 ( or, in radians : 5π/7 )

I don't remember if the 120 degree angle error is only present in one of the images of the lower left hand fragment of a regular septagon, or if it is also present in the book text. ( EDIT : Not present in book text )

Also, I don't know if this has been covered before -- if it has then I apologize for the redundancy.

jdb2

Well, I *swear* I remember seeing an image of the lower left portion of a septagon sitting levelly on one of its sides made up of Barrens fire trails with a "120" in the bottom left corner inside the septagon, but I can no longer find it -- it's like it's been excised from the ebook. I thought I may have highlighted it and made a note on my Kindle, but that is gone too if I indeed did highlight it.

So, just ignore my -- now seemingly erroneous -- post...

jdb2