Leonardo Fibonacci (c1175-1250) was travelled widely in Barbary (Algeria), Egypt, Syria, Greece, Sicily and Provence. In 1200 he returned to Pisa and used the knowledge he had gained on his travels to write Liber abaci in which he introduced the Latin-speaking world to the decimal number system. The first chapter of Part 1 begins:
These are the nine figures of the Indians: 9 8 7 6 5 4 3 2 1. With these nine figures, and with this sign 0 which in Arabic is called zephirum, any number can be written, as will be demonstrated.
Besides this Fibonacci also took part in mathematical competitions and challenges (these were commonthen). For example, in 1225 Fibonacci took part in a tournament at Pisa ordered by the emperor himself, Frederick II. Competitions could include puzzles such as this:
Beginning with a single pair of rabbits, if every month each productive pair bears a new pair, which becomes productive when they are 1 month old, how many rabbits will there be after n months?
The answer? (xn+1 = xn + xn-1) has become known as the Fibonacci sequence. It begins with 0 and 1. It follows the simple simple rule: Add the last two numbers to get the next.
0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987,…
Why the interest in Fibonacci today? I was walking down a street in my home town (a street I have often walked on before) and I noticed that someone had decorated a building with the Fibonacci sequence.
Was this art? or is there a deeper meaning? Perhaps even a conspiracy? Decorating buildings using mathematical formulas and principles was hardly the vogue since this house was built!
