The Fibonacci series, a sequence of numbers first described by Leonardo of Pisa (known as Fibonacci) in his Liber Abaci (1202); Fibonacci numbers are the basis for the Golden Mean. It is a deceptively simple sequence, in which the last number in the sequence is the sum of the previous two:

0+1=1; 1+1=2; 2+1=3; 3+2=5; 5+3=8; 8+5=13; etc.

   The ratio of the two added numbers leads to both an algebraic and geometric representation of the Golden Mean. Numerically, it is 0.61803, rounded to 0.62 for ease. A simple graphical representation shows a=1 x 0.62 and b = a x 0.62.