Today is Fibonacci (Leonardo of Pisa) Day. Fibonacci sequence starts like this: 0,1,1,2,3,5,8,13 and so on. Each number is the sum of the two numbers before. When using squares with those widths we get a spiral like the one on the tail of the chamaleon. You can find it also on: flower petals; seed heads; pinecones; shells; spiral galaxies etc.