diff --git a/t.php b/t.php
index e2d53ce..966ce07 100644
--- a/t.php
+++ b/t.php
@@ -1 +1,48 @@
-hello, test;
+<?php
+
+// class Bar implements IteratorAggregate
+// {
+//     private function foo()
+//     {
+//         $i = 5;
+//         while ($i--)
+//             yield $i;
+//     }
+
+//     public function getIterator()
+//     {
+//         return $this->foo();
+//     }
+// }
+
+// $bar = new Bar();
+// foreach ($bar as $item) {
+//     var_dump($item);
+// }
+
+function gen()
+{
+    $i = 1;
+    while (true) {
+        yield $i += yield;
+        echo $i, "\n";
+    }
+}
+
+$gen = gen();
+var_dump($gen->send(3));
+$gen->next();
+echo "----\n";
+var_dump($gen->send(4));
+$gen->next();
+echo "----\n";
+$gen->send(5);
+$gen->next();
+echo "----\n";
+$gen->send(6);
+$gen->next();
+echo "----\n";
+$gen->send(7);
+$gen->next();
+echo "----\n";
+