Fractal Geometry "Clouds are not spheres, mountains are not cones, coastlines are not circles, and bark is not smooth, nor does lightning travel in a straight line.” Benoit Mandelbrot Fractal tree branch made by algorithmic drawing Traditional Japanese woodblocks (left) and their modern fractal counterparts (right). Hokusai , The Great Wave Off Kanagawa Fractal generated landscape by Vistapro Star Trek II: The Wrath of Khan, Genesis Effect PRZEMYSLAW PRUSINKIEWICZ Professor, Department of Computer Science University of Calgary “I apply methods of computer science to gain a better understanding of the emergence of forms and patterns in nature.” spiral phyllotaxis spiral arrangement leaves, florets, or seeds. modeling lilac inflorescence Generation 1 Generation 2 Generation 4 Generation 6 Generation 12 Iterated Function System Rule 1: x' = 0 y' = 0.16y Rule 2: x' = 0.85x + 0.04y y' = –0.04x + 0.85y + 0.16 Rule 3: x' = 0.20x – 0.26y y' = 0.23x + 0.22y + 0.16 Rule 4: x' = –0.15x + 0.28y y'= 0.26x + 0.24y + 0.08 Fractals are mathematical hydras. They replicate themselves by fragmentation. You look at a fractal pattern and you see a form; then you look closely at a particular region of the pattern, and you see the same form all over again, only much smaller this time. A repetition of the same structural form, a self-similar solution that goes on ad infinitum. Paul W. Carlson, fractal artist Conic Sections Ptolemaic View of the Universe Dante’s Divine Comedy Clockwork Universe a0 r= 1 + e cosq a0 a= 1 - e2 e > 1 hyperbola e = 1 parabola e < 1 ellipse e = 0 circle Spherical Triangle Escher’s Circle Limit IV The First Monster Curve Giuseppe Peano, 1890 Koch Snowflake Helge von Koch 1870 - 1924 The Ultimate Fractal Benoit Mandelbrot Mandelbrot Set zn+1 = zn2 + c EUCLIDEAN FRACTAL - traditional ( > 2000 - modern monsters yr old ) ( 100 years old ) - deals with lines, spheres, cylinders and cones - these forms can be scaled - no specific size or scale - self similarity is apparent with magnification - shapes described by formula - shapes defined by a recursive algorithm - shapes evolve - appropriate for nature - suits man-made objects Julia Set GASTON MAURICE JULIA 1893-1978 Euclidean geometry, in which every line has exactly one parallel through any point hyperbolic geometry, in which infinitely many parallels to a line can go through the same point