Sierpinski Simple
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WHAT IS IT?
The fractal that this model produces was discovered by the great Polish mathematician Waclaw Sierpinski in 1916. Sierpinski was a professor at Lvov and Warsaw. He was one of the most influential mathematicians of his time in Poland and had a worldwide reputation. One of the moon's craters is named after him.
HOW IT WORKS
The basic geometric construction of the Sierpinski tree goes as follows. We begin with a single point on the plane and then apply a repetitive scheme of operations to it. Grow a "spider" centered at this point by drawing three equal line segments directed to the vertices of an equilateral triangle. Then at each vertex of the triangle repeat the construction --- grow a similar "spider" only scale it down by the factor of two.
. Step 0: Start with a point
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| Step 1: Grow a spider
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| Step 2: Repeat step 1
/ \
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/ \ / \
/ \ / \
The Sierpinski tree is closely related to the class of fractals called Sierpinski Carpets which includes the famous Sierpinski Triangle or as it is usually called The Sierpinski Gasket.
The features that characterize the Sierpinski tree are self-similarity and connectedness. It is not always easy to determine if a fractal is connected. It took almost a decade to prove the connectedness of the famous Mandelbrot set. However connectedness is apparent from the way Sierpinski tree is generated; at each iteration the set is connected.
HOW TO USE IT
Push the SETUP button to clear the world and initialize globals. Press repeatedly on the GO ONCE button to perform iterations of the Sierpinski algorithm.
THINGS TO NOTICE
Notice the use of hatch primitive which makes it so simple to generate fractals like Sierpinski tree.
THINGS TO TRY
Try to write a program that draws other self-similar shapes. For instance try the rule below
. Step 0
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__|___________|__ Step 2
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The resulting fractal is known in Algebraic Topology as a Universal Covering of the Figure Eight.
NETLOGO FEATURES
Notice how the curves are formed using several agents following the same rules. Also, take note of the use of the hatch command.
RELATED MODELS
L-System Fractals
HOW TO CITE
If you mention this model in a publication, we ask that you include these citations for the model itself and for the NetLogo software:
- Wilensky, U. (1998). NetLogo Sierpinski Simple model. http://ccl.northwestern.edu/netlogo/models/SierpinskiSimple. Center for Connected Learning and Computer-Based Modeling, Northwestern Institute on Complex Systems, Northwestern University, Evanston, IL.
- Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern Institute on Complex Systems, Northwestern University, Evanston, IL.
COPYRIGHT AND LICENSE
Copyright 1998 Uri Wilensky.
This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.
Commercial licenses are also available. To inquire about commercial licenses, please contact Uri Wilensky at uri@northwestern.edu.
This model was created as part of the project: CONNECTED MATHEMATICS: MAKING SENSE OF COMPLEX PHENOMENA THROUGH BUILDING OBJECT-BASED PARALLEL MODELS (OBPML). The project gratefully acknowledges the support of the National Science Foundation (Applications of Advanced Technologies Program) -- grant numbers RED #9552950 and REC #9632612.
This model was converted to NetLogo as part of the projects: PARTICIPATORY SIMULATIONS: NETWORK-BASED DESIGN FOR SYSTEMS LEARNING IN CLASSROOMS and/or INTEGRATED SIMULATION AND MODELING ENVIRONMENT. The project gratefully acknowledges the support of the National Science Foundation (REPP & ROLE programs) -- grant numbers REC #9814682 and REC-0126227. Converted from StarLogoT to NetLogo, 2001.
Comments and Questions
turtles-own [ modulus ] ; create a turtle and set its initial location and modulus to setup clear-all crt 1 [ set heading 0 setxy 0 -3 set modulus 0.5 * max-pycor pen-down ] reset-ticks end ; ask the turtles to go forward by modulus, create a new turtle to ; draw the next iteration of sierpinski's tree, and return to its place to grow hatch 1 [ fd modulus set modulus (0.5 * modulus) ] ; new turtle's modulus is half its parent's end ; draw the sierpinski tree to go ask turtles [ repeat 3 [ grow right 120 ; turn counter-clockwise to draw more legs ] die ; kill all the living turtles ] tick end ; Copyright 1998 Uri Wilensky. ; See Info tab for full copyright and license.
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Attached files
| File | Type | Description | Last updated | |
|---|---|---|---|---|
| Sierpinski Simple.png | preview | Preview for 'Sierpinski Simple' | over 11 years ago, by Uri Wilensky | Download |
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