PHP Functional programming

I need to do a few functional programming in PHP, here is the code but it only prints out "arg2" but not "arg1". Thank you.

function prints($arg1, $arg2)
{
  echo $arg1. $arg2;
}


function applyOne($arg1)
{
  $f =  create_function('$arg2', 'return prints("$arg1", $arg2);');
  return $f;
}

$printFunction = applyOne("arg1");

$printFunction('arg2');

PHP:

 

$arg2 is unset in your applyOne function. What do you want it to output?

 

I want it to output 'arg1arg2';