# A Fibonacci for Fibonacci Fibonacci

He
taught
the west
how to use
just ten numerals
to track the flow of goods and gold
and the spiraling growth of sunflowers and snail shells.

I enjoyed writing a cinquain for Adelaide Crapsey, the inventor of the form. So today I thought I’d write a Fibonacci for the mathematician, Leonardo of Pisa, who is known as Fibonacci. Fibonacci lived in the 12th century and was the son of an Italian merchant. He grew up traveling throughout the Mediterranean. His natural interests led him to study mathematics wherever he traveled. In North Africa he learned about the Hindu-Arabic numeral system. He quickly understood its advantages over Roman numerals. In his book Liber Abaci, he argues for their use and describes their practical application. As an example, he solves the question of how many rabbits you would have at the end of the year if you started with a pair and each pair produced another pair every month. The answer follows what we now call the Fibonacci sequence, in which each subsequent number is the sum of the two previous numbers. Thus the sequence begins 1, 1, 2, 3, 5, 8, 13. The sequence also describes the spiraling growth of many natural objects, including the sunflower, the pinecone, and the snail shell. A Fibonacci poem takes the numbers in the sequence as the number of syllables in each line.

I hope you like it.

See you tomorrow.

Liz

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