%%This postscript program will generate an IFS fractal image on a postscript
%%printer.
%%
%%There are three things that can be changed to alter the image produced.
%%
%%1. The value following the /numdots is the number of iterations that
%%   will generate points in the resulting image.
%%2. The values in the array following the /transforms statement controls
%%   the overall image generation
%%3. The values in the array following the /probabilities determines the
%%   effect of each row of the /transforms array on the resulting image.
%%
%%For those of you that are not familar with postscript code, the two numbers
%%in the last line preceeding the translate command control the position of
%%the image on the page relative to the lower left corner and the value
%%prior to the "dup scale" command in the last line controls the size of
%%the printed image.
%%
%%Cut as indicated and send the result to your favorite postscript printer.
%%
/problistcreate
{
    mark /counter 0 def probabilities
    {
        128 mul round cvi { transforms counter get }
        repeat /counter counter 1 add def
    }
    forall counttomark 128 sub neg dup 0 gt
    { [1 0 0 1 0 0] repeat }
    {pop} ifelse] /problist exch def
} bind def

/doit
{
    problistcreate 1 1 20
    {problist rand -24 bitshift get transform 2 copy moveto .001 10 rlineto}
    repeat newpath numdots
    {
        problist rand -24 bitshift get transform 2 copy moveto .001 0 rlineto
        stroke
    } repeat
} bind def

%% /// demo - remove or alter before reuse ///

/numdots 10000 def  % increase for denser image; decrease for faster print

/transforms
[
     [ 0 0 0 .16 0 0]
     [.2 .23 -.26 .22 0 1.6]
     [-.15 .26 .28 .24 0 .44]
     [.85 -.04 -.04 .85 0 1.6]
] def

/probabilities [.01 .07 .07 .85] def

1 setlinecap 0 setlinewidth 300 100 translate 50 dup scale doit showpage quit


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