define("WIDTH", 400);
define("HEIGHT", 400);
$img = imagecreate(WIDTH, HEIGHT);
$bg = $white = imagecolorallocate($img, 0xFF, 0xFF, 0xFF);
$black = imagecolorallocate($img, 0, 0, 0);
imagerectangle($img, 0, 0, WIDTH-1, HEIGHT-1, $black);
$center_x = (int)WIDTH/2;
$center_y = (int)HEIGHT/2;
$angle = 0;
$radius = 0;
while($radius <= WIDTH ) {
imagearc($img, $center_x, $center_y, $radius,
$radius, $angle-5, $angle, $black);
$angle += 5;
$radius++;
}
header("Content-Type: image/png");
imagepng($img);
?>