Sunday, October 19, 2008

Fibonacci spiral in nature

Fibonacci spiral is a line, which is created by drawing arcs connecting the oppposite corners of the squares in Fibonacci tiling, which is constructed of squares whose sides are successive Fibonacci numbers in length.
Fibonacci tiling
Fibonacci spiral
Fibonacci spiral exists in many objects of wildlife. It's one ob the basic curve, which you can see in small shells of nautilus and even in spirals of galaxies.

Arrangement of seeds in sunflower is an example of Fibonacci spiral among plants.

Hurricane is one of the most destructive power on Earth.

You can see Fibonacci spiral even in shapes of galaxies.

Although Nautilus shell looks very similar to Fibinacci spiral, it does not. Ivars Peterson in his article Sea Shell Spirals proved this fact. Nevertheless, Nautilus shell is one of examples of fractals in nature.

Fibonacci spiral inspired some artist to use it in their artworks. Below you can see an artwork by Petar Milivojevic named Gaia's gift.

Sunday, October 12, 2008

Fractal tilings

Fractal shapes can be used as tiles for filling plane. In most cases variations of the Koch snowlake are used. A simple Koch snowflake is represented to the right. To create a set of tiles, which can be used for filling whole plane, we need another variations of the snowlake which exactly match to all convexes and concaves of the first figure.

Two variations of such kind of tilings were represented on Briges 2008 conference, which took place in Leeuwarden (Holland). Both were realized in wood. We see that several kinds of fractal tiles were used in both cases. 

Koch tiling by Edmund Harris

Pentagonal Koch tiling by Chaim Goodman-Strauss

More mathematical issues about fractal tiles you can read in the article about Rauzy fractal.