$pic = imagecreatetruecolor(600,600);
$brush = imagecreate(100,100);
$brushtrans = imagecolorallocate($brush, 0, 0, 0);
imagecolortransparent($brush, $brushtrans);
for ($k = 1; $k < 8; ++$k) {
$color = imagecolorallocate($brush, 255, $k * 15, 0);
imagefilledellipse($brush, $k * 5, $k * 5, 5, 5, $color);
}
imagesetbrush($pic, $brush);
imageellipse($pic, 300, 300, 350, 350, IMG_COLOR_BRUSHED);
imagepng($pic);
imagedestroy($pic);
imagedestroy($brush);
?>