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From: james@tcom.stc.co.uk (James Rouse)
Newsgroups: comp.graphics
Subject: Re: Fractals
Keywords: Postscript, Barnsley's fractals
Message-ID: <764@jura.tcom.stc.co.uk>
Date: 23 Feb 89 10:35:11 GMT
Organization: STC Telecomms, Access Systems Engineering, Harlow. ESSEX
Lines: 37


Charles Culmer writes of Barnsley's method for generating fractals.  I saw an
Equinox program on chaos and that also described his fern; so I drew it.
The following is a postscript program, sorry you'll have to convert it.
(Yes Adrain the code probably is horrible :-))
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%!
-50 0 translate
/Helvitica findfont 10 scalefont setfont
/xpos 350 def
/ypos 383 def
xpos ypos moveto
/cho                                    %generate a random number from 0 to 2 
{/num rand 3 mod def} def               %mod 3 on 2^31-1
/one
{/xpos xpos 100 add 2 div def           %point one at 100,600
/ypos ypos 600 add 2 div def} def
/two
{/xpos xpos 600 add 2 div def           %point two at 600,600
/ypos ypos 600 add 2 div def} def
/three
{/xpos xpos 350 add 2 div def           %point three at 350,167
/ypos ypos 167 add 2 div def} def
1 1 5000 { pop                          %plots 5000 points and takes ~2mins.
cho                                     %increase the 5000 for more points.
num 0 eq {one} if
num 1 eq {two} if
num 2 eq {three} if
xpos ypos moveto (.) show} for          %plot a point at the currentpoint.
showpage


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I hope this helps,
   Jim Zaxspeed