# Numbers and spirals

Compare the Fibonacci numbers with the squares in the tiling.

By drawing arcs connecting the opposite corners of squares in the tiling you can create a spiral. This socalled Fibonacci spiral approximates the golden spiral whose growth factor is related to the golden ratio.

Fibonacci numbers appear in biological settings, such as arrangement of leaves on a stem in plants, the fruitlets of a pineapple and the bracts on a pine cone. Upon observation of the cone e. g., one can notice two spirals, one to the left (clockwise) and the other one to the right (counter-clockwise). Counting the spirals one gets successive Fibonacci numbers.

Find out: Which Fibonacci number follows 987?

# A fascinating movie

Can you imagine how fascinating the world of numbers can be? Watch the wonderful movie "Nature by Numbers", produced by CristÃ³bal Vila.