The Fibonacci numbers form a sequence defined by this relation (don’t be scared!):

What this means, in English, is that it is a sequence of numbers whose relationship is this: after the first two numbers, each proceeding number is the sum of the previous two numbers. For example 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233…..and so on. Quite simple, really.

Fibonacci numbers have an interesting property. When you divide one number in the sequence by the number preceding it, you are left with a number very close to 1.618. This number is called the “golden ratio,” and rectangle whose sides is equal to the golden ratio is known as a “golden rectangle.”

Fibonacci numbers are not purely artifact, they are also found in nature in an uncurling fern, the branching of trees, and leaflets of the pineapple. The Fibonacci sequence also describes the “golden spiral,” which is when a “golden rectangle” is subdivided in smaller and smaller golden rectangles (example below)–the result being a predictable spiral.

One example of a biological structure in the mammalian body which is very close to a “golden spiral” is the cochlea. It is not a perfect golden spiral, and there is individual variation between and within species.

Another close example is the shell of a mollusk, or a nautilus shell (below).

The Fibonacci sequence has been used to structure poetry, ie the syllables per line follow the Fibonacci sequence. As a former student of poetry, I couldn’t help but try my hand.

These poems are based on the Fibonacci sequence and have been published in the Science Creative Quarterly, when I wrote them about 6 months ago.

—

**Shyness**

Fish

dive

deeply,

mouths agape,

fins proud and ragged,

filtering the oceans apart

until shimmer-hooked and then flopping in boat bottoms,

when gills heave, gasp, drowning in air; eyes glaze like dropped

marbles, clouded and cracked, but holding.

—

**Ego**

She

will

nod as

you pass her

and you both will know

you are young and raw, half-bitten,

spitten in disgust like fruit picked before its season.

—–

**Heaven**

Dead

leaves

jump back

on the trees,

a reverse whirlwind

and an impossible sunset

seeking their origins, the life from whence they came.