Question: I know it's possible to have an array within an array like this.

```
Array01 (

[0] => Array
    (
        [0] => 40292633
        [1] => 412
    )

[1] => Array
    (
        [0] => 41785603
        [1] => 382
    )

[2] => Array
    (
        [0] => 48792980
        [1] => 373
    )

[3] => Array
    (
        [0] => 44741143
        [1] => 329
    )
)

```

Can you have an array in an array in an array like this?

```
Array01 (

[0] => Array
    (
       [0] => Array
       (
           [0] => 40292633
           [1] => 412
       )

        [1] => Array
       (
           [0] => 41785603
           [1] => 382
       )
    )

[1] => Array
    (
        [0] => 41785603
        [1] => 382
    )

[2] => Array
    (
        [0] => 48792980
        [1] => 373
    )

[3] => Array
    (
        [0] => 44741143
        [1] => 329
    )
)

```

What I'm curious about is how far can this go, how many arrays can you have in an array?

Answer: 
You can go infinitely deep.

**EDIT:**

There is a limit of number of elements per array, as described [here](https://stackoverflow.com/questions/3036957/php-do-arrays-have-a-maximum-size), but that is a separate issue from depth. 

Of course you need to take into consideration your machine's constraints (time and RAM), but there are no theoretical limits or restrictions from PHP for going infinitely deep.
You could test it by yourself

```
<?php
$i =0;
$array = [];
$a = &$array;
while(true) {
$a = &$a[];
$i++;
if ($i % 1000000==0){ echo $i,' ';};
}

```