"Whether or not Frank Lloyd Wright was aware of such concepts as the 'Golden Mean' and the 'Fibonacci Series' is a moot point.
Wright used nature as the basis of his geometrical abstraction. His objective was to 'conventionalize the geometry' which he found in 'Nature' -- and his method was to adopt the abstract simplification which he found so well expressed in the Japanese print.
Therefore, it is not too shocking perhaps that in this quest his work should foreshadow the 'new mathematics of nature' first put forth by Benoit Mandelbrot -- fractal geometry." -- Leonard K. Eaton