A 9-piece puzzle

Yesterday, Benjamin put together a 9-piece puzzle in record time - less than 2 minutes.  WHAT?  9 pieces?  How hard can that be?  Well, if you know my parents, they have found these 9-piece puzzles that are next to impossible to put together. The puzzle has 9 square pieces that you have to fit together.  (Again, WHAT?  Square pieces you have to fit together?  What 9 year old cannot do that in less than a minute?) The catch is that these puzzles can only be put together one way and one way only.  The sides are created in a way that they look like they will fit together in many different ways, which makes this type of puzzle extremely difficult.
We were sitting downstairs and Benjamin brought the puzzle down to work on it.  First, he said, "This one goes here, and that piece goes here..." and I was pretty much ignoring him, thinking he was going to have to spend days on it.  Pretty soon, he said, "THERE!"  I was still not sure it was correct, but when I looked at it, I was stunned!  We just burst out laughing and he ran back to tell Jim he'd done the puzzle. 
Here is the proof that Benjamin completed the puzzle and I witnessed him putting it together in less than 2 minutes.

Unfortunately, this was a fluke.  He wanted to try again, so he mixed up the pieces and could not recreate the puzzle.  Oh well.  He was thrilled with his initial accomplishment!