<?php
error_reporting(-1);

$name = "vik";

$letters = preg_split('//u', $name, -1, PREG_SPLIT_NO_EMPTY);


function ano($found, $letters) {
	if (empty($letters)) {
		echo $found . "\n";
		
	} else {
		foreach ($letters as $num => $letter) {
			$found .= $letter;
			//echo $letters[$num] . "\n";
			unset($letters[$num]);
			//print_r($letters);
			ano($found, $letters);
		}
	}
	
}
$here = "";

ano ($here, $letters);