<?php
        set_time_limit(5);
 
        $i = 6;         // Количество итераций
        $xy = 1500;     // Размер стороны картинки
 
        $img = imagecreatetruecolor($xy, $xy);
 
        $black = imagecolorallocate($img, 0, 0, 0);
        $white = imagecolorallocate($img, 255, 255, 255);
 
        $cycle = 0;
        drawCarpet(0, 0, $xy, $xy, $i);
        function drawCarpet($a, $b, $c, $d, $n) {
                global $img, $white, $cycle;
                $cycle++;
 
                if($n <= 0) return;
 
                $a1 = 2 * $a / 3 + $c / 3;
                $c1 = $a / 3 + 2 * $c / 3;
                $b1 = 2 * $b / 3 + $d / 3;
                $d1 = $b / 3 + 2 * $d / 3;
 
                imagefilledrectangle($img, $a1, $b1, $c1, $d1, $white);
 
                drawCarpet($a, $b, $a1, $b1, $n - 1);
                drawCarpet($a1, $b, $c1, $b1, $n - 1);
                drawCarpet($c1, $b, $c, $b1, $n - 1);
 
                drawCarpet($a, $b1, $a1, $d1, $n - 1);
                drawCarpet($c1, $b1, $c, $d1, $n - 1);
 
                drawCarpet($a, $d1, $a1, $d, $n - 1);
                drawCarpet($a1, $d1, $c1, $d, $n - 1);
                drawCarpet($c1, $d1, $c, $d, $n - 1);
        }
 
        imagefilledrectangle($img, 0, 0, (strlen($cycle) * 9) , 16, $white);
        imagestring($img,21,0,0,$cycle,$black);
 
        header('Content-Type: image/png');
        imagepng($img);
?>