use strict;

use GD;

my $width = 500;
my $height = 500;

my $image = GD::Image->new($width, $height);

my $white = $image->colorAllocate(255, 255, 255);
my $black = $image->colorAllocate(0, 0, 0);

$image->transparent($white);

my $ltpt = {x => 0, y => 0};
my $rbpt = {x => $width-1, y => $height-1};

do {
	($ltpt, $rbpt) = &innersquare($ltpt, $rbpt);
} while ($ltpt != -1);

binmode STDOUT;
print $image->png;
close STDOUT;

sub innersquare {
	my $lt = shift;
	my $rb = shift;

	my $rate = 100;

	my $borderlt = {x => ($lt->{'x'}+$rb->{'x'})/$rate+$lt->{'x'}, y => ($lt->{'y'}+$rb->{'y'})/$rate+$lt->{'y'}};
	my $borderrb = {x => $rb->{'x'}-($lt->{'x'}+$rb->{'x'})/$rate, y => $rb->{'y'}-($lt->{'y'}+$rb->{'y'})/$rate};

	my $newlt = {x => rand($borderlt->{'x'}-$lt->{'x'})+$lt->{'x'}, y => rand($borderlt->{'y'}-$lt->{'y'})+$lt->{'y'}};
	my $newrb = {x => rand($rb->{'x'}-$borderrb->{'x'})+$borderrb->{'x'}, y => rand($rb->{'y'}-$borderrb->{'y'})+$borderrb->{'y'}};

	return -1 if $newlt->{'x'} >= $newrb->{'x'} or $newlt->{'y'} >= $newrb->{'y'};

	$image->rectangle($newlt->{'x'}, $newlt->{'y'}, $newrb->{'x'}, $newrb->{'y'}, $black);

	return ($newlt, $newrb);
}