<?php

error_reporting(-1);
mb_internal_encoding('utf-8');

$text = "zxcvbnmnbvcxz";

$noSpaces = str_replace(" ", "", $text);
$toLower = mb_strtolower($noSpaces);

$length = mb_strlen($toLower);
$half = floor($length / 2);

for($i=0; $i<=$half; $i++){
	$sSymbol = mb_substr($toLower, $i, 1);
	$eSymbol = mb_substr($toLower, $length-1-$i, 1);
	echo "{$sSymbol}\t {$eSymbol}\t {$i}\t {-$i}\n";
	}