Brother Leonardo

Leonardo who? No, not him, the Mona Lisa bloke, the other one. Fibonacci, probably the greatest mathematician of the thirteenth century. This is him, a bit girly, but he was only 22. I'm a big fan. Freshly baptised in the 'new' Indo-Arabic numerology, him having travelled a bit because his dad was a diplomat, the first thing he did was to think about rabbits.
"Suppose a newly-born pair of rabbits, one male, one female, are put in a field. Rabbits are able to mate at the age of one month so that at the end of its second month a female can produce another pair of rabbits. Suppose that the rabbits live for ever and that the female always produces one new pair (one male, one female) every month from the second month on. How many pairs will there be in one year? "
Counting in months then, we've got:
1,1,2,3,5,8,13,21,34 (September 1st already...),55,89,144,233...
Fascinating, isn't it.You all can see the pattern and could easily find out the next number in the series.. Dividing the next larger by the previous settles down to a MAGIC number, phi, the Golden Ratio, 1·618034 . More fun here than you can shake a stick at.
I shall return later with some amusing divertimenti around the golden ratio.... In particular, concerning cauliflowers, bees and what not.