Time-delayed, two-layer switch changer function.

key-changer.php

<?php
	$key = array(

		'key0',
		'key1',
		'key2',
		'key3',
		'key4',
		'key5',
		'key6',
		'key7',
		'key8',
		'key9'

	);

	$keyNumber = count($key);

	$delay = 10;

	$time = time();

	$mask = array( 

		array(0 => 8, 1 => 5, 2 => 1, 3 => 9, 4 => 0, 5 => 6, 6 => 3, 7 => 2, 8 => 7, 9 => 4), 
		
		//0 1 2 3 4 5 6 7 8 9

		//8 5 1 9 0 6 3 2 7 4

		array(0 => 2, 1 => 4, 2 => 0, 3 => 8, 4 => 7, 5 => 1, 6 => 5, 7 => 9, 8 => 6, 9 => 3)
		
		//0 1 2 3 4 5 6 7 8 9

		//2 4 0 8 7 1 5 9 6 3

	);


	$levelOne = floor( $time / $delay ) % 2;

	$levelTwo = floor( $time / $delay ) % $keyNumber;


	$result = $key[$mask[$levelOne][$levelTwo]];

	echo $result;