The Fibonacci sequence is named after Leonardo Pisano Bigollo of Pisa known as Fibonacci (1170-1250), the great European mathematician of the middle ages. Fibonacci is known to the modern world for popularizing the Hindu-Arabic numeral system in Europe, primarily through the publication in 1202 of his Liber Abaci (Book of the Abacus or Book of Calculation), and for the number sequence named after him.

0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584 ...

Fibonacci numbers are intimately connected with the Golden Section, also known as the Golden Mean, Golden Ratio and Divine Proportion in mathematics, art, and architecture. It is a ratio or proportion defined by the number Phi = 1.618 033 988...

A Fibonacci spiral, which approximates a Golden Spiral, is created by drawing quarter-circle arcs connecting the opposite corners of squares laid out in the Fibonacci tiling format; our logo uses squares of sizes 1, 1, 2, 3, 5, 8, 13, 21, 34 and 55.