3v4l.org

run code in 300+ PHP versions simultaneously
<?php $f = function ($p, $w) use (&$f) { return ($w) ? $p = $f($p + 0.25, $w - 1) : $p; }; foreach (explode(' ', '4 40 10 100 1') as $p) { echo $f($p, 5) . '<br>' . PHP_EOL; }

preferences:
38.14 ms | 402 KiB | 5 Q