I am an artist and I have recently become very interested in Josef Muller-Brockman's grid systems however I am very new to this sort of system and would like to better understand the math at work in the construction of the grids so that I can construct a 20 cell grid for a page that is the golden ratio (ie. the height is 1.618 * the width).

I am using the 20 grid on page 77 of Josef Muller-Brockman's Grid Systems in Graphic Design as a reference, however the page the book is printed on is not exactly a golden ratio, nor is the grid area a true golden ratio.

Please forgive me if any of this is rudimentary as I have never dealt with anything like this since high school geometry, but does anybody have any idea how I would go about constructing a similar grid in Indesign where the page is a golden ratio, and so is the bounding box of the grid?

I have included a scan of page 77 from the Josef Muller-Brockman book.

Any suggestions would be greatly appreciated

Thanks so much!

ps. Please let me know if there is any other information or any files i could provide that would be helpful