<?php
function func($indexes){
	$k=0;
	$desc = array();

	foreach ($indexes as $gointo){
		foreach ($gointo as $item){
			if ($k>3) break;
			$desc[$k] = $k*$k;
			$k++;
		}
	}
	print_r ($desk);
}

$indexes = array( 3 => (1,2,3,4,5), 6 = > (4,5,4,3,8) );

func($indexes);
?>

$desc = array();

print_r ($desk);