Online PHP editor | refs for JO3RX

<?php $arr = [20,22,29,40,67,35,98,200,205,220]; function subArrayValues($array) { static $firstRound = 0; if (count($array) < 2){ echo $array[0]; return; } $prevVal = null; $newArray = []; foreach ($array as $val){ if ($prevVal !== null){ $result = $val - $prevVal; $newArray[] = $result; } $prevVal = $val; } if ($firstRound) echo implode(",", $array) . "\n"; $firstRound++; subArrayValues($newArray); } subArrayValues($arr);