At first glance, a pineapple, a violin, and a turtle’s shell appear to have little in common. Yet the structure of each shares a startling similarity. That amazing link is the Fibonacci Sequence, in which the sum of two sequential numbers equals the third immediately following them. These numbers, 1, 2, 3, 5, 8, 13, 21, ad infinitum, manifest themselves abundantly in nature and the arts.

In a talk on March 22 at Main Campus, Assistant Professor of Mathematics Jeannie Galick demonstrated how the sequence is discovered in a variety of places. Beginning with a pineapple, she showed how the bumps on its surface are not random, but rather laid out in spiraling rows of Fibonacci numbers. The same sequence underlies the arrangement of a pine cone’s closed petals, a sunflower’s seeds, and a hyacinth’s petals and leaves, optimizing the plants’ reception of light and moisture. Sections of a turtle’s shell equal Fibonacci numbers, as do branches, leaves and petals of a hyacinth—even segments of the human body.

The sequence was first discovered in the West by Leonardo of Pisa, popularly known as Fibonacci, an outstanding thirteenth-century mathematician who also introduced Arabic numerals and the decimal system to Europe from North Africa. He is especially famed for the Rabbit Problem, which computes the family tree of rabbit populations over generations.

The ratio of adjacent Fibonacci numbers is known as The Golden Ratio, approximately 1.618, denoted by the Greek letter phi. The ratio is found throughout architecture, art and music. It appears in the Parthenon, in the spacing of themes in Beethoven’s Fifth Symphony and in the works of such diverse artists as Rembrandt, Michaelangelo, Da Vinci, Seurat, and Dali.

Fibonacci numbers and The Golden Ratio are everywhere for you to find. The next time you visit New York City, take a closer look at the United Nations building; it is a golden rectangle. And if you go to see the soon-to-be-released movie of Brown’s The Da Vinci Code, discover how the Fibonacci code plays out in the plot.