Koch Curve, step 1. 2 kB.

The Koch curve was first described by the Swedish mathematician Helge Koch in 1904 -- long before fractals were thought of.

To construct a Koch curve, begin with a triangle with sides of length 1, so its perimeter is of length 3.

Koch Curve, step 2. 2 kB.

Onto the middle of each side, add a new triangle one third of the size of the original one.

Koch Curve, step 3. 2 kB.

The length of the new perimeter is
3 x 4/3 = 4.

Koch Curve, step 4. 3 kB.

The same process of adding a new triangle one third of the size of the previous ones onto the middle of each side is repeated. After n steps the perimeter has length
3 x (4/3)n.

Koch Curve, step 5. 2 kB.

The perimeter of the resulting shape becomes infinitely long, but surrounds a finite area. While a simple one-dimensional line fills no space at all, the Koch curve, with infinite length crowding into finite area, does fill space: so it is more than 1- but less than 2-dimensional; in fact, it can be calculated to be of dimension 1.2618.

Benoit Mandelbrot described this 'snowflake'-shape as ''a rough but vigorous model of a coastline'' -- like a coastline, it is self-similar in such a way that it keeps 'becoming longer' the more closely one looks.

 
 
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