How to echo lines of text vertically in PHP?

I got this problem somewhere, and I want to know how to solve this using PHP. Given this text:

$str = '
PHP is a
widely-used

general-purpose
server side

scripting
language
';

How to echo the text vertically like the given below:

      g        
      e        
      n        
      e        
  w   r s      
  i   a e      
  d   l r   s  
P e   - v   c l
H l   p e   r a
P y   u r   i n
  -   r     p g
i u   p s   t u
s s   o i   i a
  e   s d   n g
a d   e e   g e

I will select the simpler and more elegant code as the answer.

Solution

As others have already demonstrated, array_map is able to do the flip over which is basically the main problem you need to solve. The rest is how you arrange the code. I think your version is very good because it's easy to understand.

If you're looking more to some other extreme, handle with care:

$str = 'PHP is a
widely-used

general-purpose
server side

scripting
language';
    
$eol = "\n";
$turned = function($str) use ($eol) {
    $length = max(
        array_map(
            'strlen',
            $lines = explode($eol, trim($str))
        )
    );
    $each = function($a, $s) use ($length) {
        $a[] = str_split(
            sprintf("%' {$length}s", $s)
        );
        return $a;
    };
    return implode(
        $eol,
        array_map(
            function($v) {
                return implode(' ', $v);
            },
            call_user_func_array(
                'array_map',
                array_reduce($lines, $each, array(NULL))
            )
        )
    );
};
echo $turned($str), $eol;

Gives you:

      g        
      e        
      n        
      e        
  w   r s      
  i   a e      
  d   l r   s  
P e   - v   c l
H l   p e   r a
P y   u r   i n
  -   r     p g
i u   p s   t u
s s   o i   i a
  e   s d   n g
a d   e e   g e

This fixes the output of the other answer, which was incorrect (now fixed).