which design pattern is used in the code bellow

Can someone please tell me which design pattern is used in the code bellow? ``` class UnixText { function write($txt){echo $txt;} function lf() {echo "\n";}

    }
    
    class MSWindowsText
    {
    function write($txt){echo $txt;}
    function crlf()   {echo "\r\n";}

    }

    interface Writer
    {
    function write($txt);
    function newLine();
    }

    class UnixWriter implements Writer{
    private $target;

    public function __construct($unixText){$this->target=$unixText; }
    function write($txt){$this->target->write($txt);}
    function newLine(){$this->target->lf();}
    }

    class MSWindowsWriter implements Writer{
    private $target;

    public function __construct($winText){$this->target=$winText;   }
    function write($txt){$this->target->write($txt);}
    function newLine(){$this->target->crlf();}
    }
    ```