For more information about algorithms, please help.

For more information about algorithms, see $ arr & nbsp; array (& nbsp; A, & nbsp; & nbsp; B, & nbsp; C), & nbsp; array (1, & nbsp; 2, & nbsp; 3, & a question about algorithms, please help
$ Arr = array (
Array ("A", "B", "C "),
Array ("1", "2", "3", "4 "),
Array ("X", "Y", "Z "),
....................................
);
How to print such a number as below (the size of the array is not fixed)

A 1 X
A 1 Y
A 1 Z
A 2 X
A 2 Y
A 2 Z
A 3 X
A 3 Y
A 3 Z
A 4 X
A 4 Y
A 4 Z

B 1 X
B 1 Y
B 1 Z
B 2 X
B 2 Y
B 2 Z
B 3 X
B 3 Y
B 3 Z
B 4 X
B 4 Y
B 4 Z

C 1 X
C 1 Y
C 1 Z
C 2 X
C 2 Y
C 2 Z
C 3 X
C 3 Y
C 3 Z
C 4 X
C 4 Y
C 4 Z
------ Solution --------------------
This meets your output requirements

$arr = array(
  array( "A",  "B",  "C"),
  array("1",  "2",  "3", "4"),
  array("X",  "Y",  "Z"),
);
 
function foo($d) {
  $r = array_pop($d);
  while($d) {
    $t = array();
    foreach(array_pop($d) as $k1=>$x) {
      foreach($r as $k2=>$y) $t[] = "$x $y";
    }
    $r = $t;
  }
  return $r;
}
print_r(foo($arr));

Array
(
    [0] => A 1 X
    [1] => A 1 Y
    [2] => A 1 Z
    [3] => A 2 X
    [4] => A 2 Y
    [5] => A 2 Z
    [6] => A 3 X
    [7] => A 3 Y
    [8] => A 3 Z
    [9] => A 4 X
    [10] => A 4 Y
    [11] => A 4 Z
    [12] => B 1 X
    [13] => B 1 Y
    [14] => B 1 Z
    [15] => B 2 X
    [16] => B 2 Y
    [17] => B 2 Z
    [18] => B 3 X
    [19] => B 3 Y
    [20] => B 3 Z
    [21] => B 4 X
    [22] => B 4 Y
    [23] => B 4 Z
    [24] => C 1 X
    [25] => C 1 Y
    [26] => C 1 Z
    [27] => C 2 X
    [28] => C 2 Y
    [29] => C 2 Z
    [30] => C 3 X
    [31] => C 3 Y
    [32] => C 3 Z
    [33] => C 4 X