And my favorite

Inspiring Things
Originally uploaded by wokka

the nautilus shell. The spiral here is almost always a perfect fit for the golden spiral. Just lovely!

And thus concludes your mini pictoral lesson on the Fibonacci numbers in nature.

succulent

succulent spiral
Originally uploaded by lakerae

Cactus or succulents are another group of plants which grow according to this principle. Count aloevera in this group as well.

leaf spiral

fibonacci green
Originally uploaded by R80o (Mark Strozier)

To my mind, the most beautiful application of Fibonacci numbers is in the spiral curve of many natural objects - a nautilus shell, a fern, or a leaf as seen here. For more information check out this piece about the golden spiral.

Pinecone

the Fibonacci sequence in action yet again
Originally uploaded by ehoyer

Pine cones are yet another natural phenomena which grow according to the Fibonacci sequence. The number of spirals in each direction are usually two consecutive Fibonacci numbers, and sometimes even the number of spines per spiral is as well.

123 posts!

SunFlower: the Fibonacci sequence, Golden Section
Originally uploaded by lucapost

So must people mark their 100th post, or some other such number, but I'm a math teacher...so I don't think I'll do it quite the same way. 123 seems like a great number to me. 3 consecutive integers. The first three natural numbers. Perhaps even more striking for me 3 of the first numbers in the Fibonacci sequence (1,1,2,3,5,8,13...) My all time favorite sequence of numbers. So I think I'll dedicate the next 5 posts (yeah for the next fib number) to cool images which reflect the Fibonacci sequence in some way. This one from lucapost on flickr has a great writeup about the Fibonacci sequence.