<?php
class Page {
                 public $title;
                 public $content;
                 public $footer;
                 public function __construct($t,$c,$f) {
                        $this->title = $t;
                        $this->content = $c;
                        $this->footer = $f;
                 }
                 public function render_body() {
                        $str = '<h1>'.$this->title.'</h1>';
                        $str .= '<p>'.$this->content."</p>";
                        $str .= "<p style='font-size=8px'>".$this->footer."</p>";
                        return $str;
               }
              public function test() {
                       return $this->render_body();
              } 
}

class Index extends Page {
            public $slide;
            public $news;
            public function __construct($t,$c,$f,$s,$n) {
                    parent::__construct($t,$c,$f);
                   $this->slide = $s;
                   $this->news = $n;

          }
          public function render_body() {
                  $str = parent::render_body();
                  $str.="<p>".$this->slide."</p>";
                  $str.="<p>".$this->news."</p>";
                  return $str;
         } 
}

class Poly {
         public $ob;
         public function get_ob(Page $var) {
                $this->ob[] = $var;
         }
        public function get_result() {
               foreach($this->ob as $item) {
               echo $item->test();
               }
        }
}
$poly = new Poly();
$page = new Page('Page','hello i am page','footer');
echo $page->render_body();
$index = new Index ('INDEX','HELLO I am index','footer','slide_show','news');
echo $index->render_body();
?>