problema de matriz aleatoria de PHP

function addFoils(){
global $board, $boardData;
for($row = 0; $row < $boardData["height"]; $row++){// for my rows
 for ($col = 0; $col < $boardData["width"]; $col++){//for my cols
  if($board[$row][$col] == "."){//.means to add letter to the cell
   $newLet = $_REQUEST["wordList"];//array from html wordlist
    $newLet = strtoupper($newLet);//convert to upper case
     $firstLetter = substr($newLet,0,1);//picks out first letter
      $board[$row][$col] = str_shuffle($firstLetter);//shuffles wordlist
            }
        }
    }
}

<?php
 
function addFoils()
{
    global $board, $boardData;
   
    // For my rows
    for($row = 0; $row < $boardData["height"]; $row++)
    {
        // For my cols
        for($col = 0; $col < $boardData["width"]; $col++)
        {
            // The "." means to add letter to the cell
            if($board[$row][$col] == ".")
            {
                // Array from html wordlist
                $newLet = $_REQUEST["wordList"];
               
                // Convert to upper case
                $newLet = strtoupper($newLet);
               
                // Shuffles wordlist
                $board[$row][$col] = str_shuffle($newLet);
               
                // Picking the first letter as the random one
                $randLetter = substr($newLet, 0, 1);
            }
        }
    }
}
?>