perl-scripts/GD/chaos_game_tetrahedron.pl

#!/usr/bin/perl

# Daniel "Trizen" Șuteu
# License: GPLv3
# Date: 25 August 2016
# https://github.com/trizen

# Chaos game, generating a Sierpinski Tetrahedron.
# https://en.wikipedia.org/wiki/Chaos_game

use 5.010;
use strict;
use warnings;

use Imager;

my $width  = 2000;
my $height = 2000;

my @points = (
    [int($width/2),                      0],
    [            0, int($height-$height/4)],
    [     $width-1, int($height-$height/4)],
    [int($width/2),              $height-1],
);

my $img = Imager->new(
                      xsize    => $width,
                      ysize    => $height,
                      channels => 3,
                     );

my $color = Imager::Color->new('#ff0000');
my $r = [int(rand($width)), int(rand($height))];

foreach my $i (1 .. 200000) {
    my $p = $points[rand @points];

    my $h = [
        int(($p->[0] + $r->[0]) / 2),
        int(($p->[1] + $r->[1]) / 2),
    ];

    $img->setpixel(
        x     => $h->[0],
        y     => $h->[1],
        color => $color,
    );

    $r = $h;
}

$img->write(file => 'chaos_game_tetrahedron.png');