error_reporting(E_ALL^E_NOTICE);

$bannerResult = mysql_query("SELECT * FROM table WHERE page='cat'");

$banners = array();

if(mysql_num_rows($bannerResult)==0){
  echo'empty';
}
else
{
while($row=mysql_fetch_assoc($bannerResult))
{
    $banners[] = new Banner($row);
}


shuffle($banners);


$bannerGroups = array_chunk($banners,1);


        foreach($bannerGroups[0] as $ban)
        {
            echo '<li class="right1">'.$ban->html().'</li>';
        }

                foreach($bannerGroups[1] as $ban)
        {
            echo '<li class="left1">'.$ban->html().'</li>';
        }

                foreach($bannerGroups[2] as $ban)
        {
            echo '<li class="right1">'.$ban->html().'</li>';
        }

                foreach($bannerGroups[3] as $ban)
        {
            echo '<li class="left1">'.$ban->html().'</li>';
        }
}