Fractal Figures

The fractal figures below are both generated using a String rewriting system. The Applet uses a seed string, called an axiom and then applies a number of string modification rules to that axiom to generate successive generations of the fractal. The resulting strings can then be parsed by a parser that is similar to a Logo Turtle in that it is capable of only a few basic moves:
+
rotate clockwise (amount specified in attributes)
-
rotate counterclockwise
f
move forward one unit (scaled automatically to fit)
F
draw a line while moving forward one unit

You can look at the source for this Applet by clicking here.


This first figure is a rendering of the von Koch snowflake curve which is generated from the axiom "F" using the single rule "F => F-F++F-F". It draws successive generations with one second delays between them. You can click on the figure to restart the fractal from the beginning.


The second figure is a rendering of the space filling Hilbert curve which has many ways you can generate it. Here, I use a more concise set of rules which involve using non-drawing characters to control the string rewrites. The axiom "X" is rewritten by either "X => -YF+XFX+FY-" or "Y => +XF-YFY-FX+". This figure draws successive generations with half second delays between them. You can click on the figure to restart the fractal from the beginning.


This document maintained by Jim Graham (Flar@bendenweyr.Eng.Sun.COM)