Element Output 098-PHP-dimensional array

<? PHP
     $ STU = Array ( Array (76,87,68),
                 Array (65,89,95),
                 Array (90,80,66),
                 Array (90,95,65));         // define a two dimensional array 
    echo '$ output element of the first array STU: <br />' ;
     print_r ( $ STU [0]);         // Since access to an array will be, so to use print_r output 
    echo '<br /> the second element of the output array $ STU: <br /> ' ;
     print_r ( $ STU [. 1 ]);
     echo ' <br /> third element array output $ STU: <br /> ' ;
     print_r (STU $ [2 ]);
     echo '<br /> output element of the fourth array $ STU: <br />' ;
     print_r ( $ STU [. 3 ]);
 >?