1, 2, 3, 5, 8, 13, 21 etc. Leonardo Bonacci of Pisa is the famous Fibonacci of the infamous Fibonacci Sequence: a mathematical sequence observed in nature and useful for unlocking Swiss bank accounts (spoiler alert - The Da Vinci Code). Clearly and concisely written in 1202 all about those pesky varmints, rabbits. ย Fibonacci was not just good with numbers, he handled words brilliantly too. ๐ฎ๐น๐ฐ ๐งฎ๐