The scales of a pineapple lie in fairly well defined ‘spirals’. In the photo, two of these are obvious, but there is a third set of almost horizontal spirals as well. Although you can’t tell this from the photo, the number of scales in these spirals turn out to be three numbers in the Fibonacci sequnce:

1, 1, 2, 3, 5, 8, 13, 21, 34, ... . Obtain a real pineapple and check it out!

There are a great number of examples where the Finbonacci sequence occurs in nature. It seems clear then that this sequence has some intrinsic connection with natural growth. However, the exact explanation of this link remains unclear.

http://www.mcs.surrey.ac.uk/Personal/R.Knott/

Fibonacci/fibnat.html

http://en.wikipedia.org/wiki/Fibonacci_number