File: test1.php

<?php
$a = array();
$a['foo'] = "Hello";
$a['foo']['bar'] = "World";
var_dump($a);

Result:

Reveal Answer

$ php test1.php 
array(1) {
  ["foo"]=>
  string(5) "Wello"
}

File: test2.php

<?=(True ? "Foo" : True ? "Bar" : "Biz");?>

Result:
Reveal Answer

$ php test2.php 
Bar

File: test3.php

<?php </script> echo "foo";?>

Result:
Reveal Answer

$ php test3.php 
 echo "foo";?>