Puzzles.

How Zachary works a jigsaw puzzle:

Opens the box.  Dumps all the pieces out on the floor.  Kicks a couple of them around.  Runs away and has a sword fight with an imaginary pirate.  Comes back to the puzzle and uses a piece as an eye patch. Kicks the pieces around some more.  Goes upstairs and puts on his superhero cape.  Saves the world a couple times.  Runs past the puzzle pieces, then grabs them all and with a flurry of hands and without actually looking at the pieces, puts them all together correctly on the first try.   Then he roars, picks it up and crashes it apart into a rainfall of puzzle pieces all while yelling "HA HA HA!  I've beaten you now!"  Total time: 10 minutes.

How Cooper works a jigsaw puzzle:

Takes one piece out of the box.  Picks up every other piece, one at a time, until he finds a match for the one he is holding.  Repeats with the next piece.  And the next.  And the next.  And so on and so forth until he is completely finished.  Then he sits back, smiles, and admires his work for a minute before methodically taking it apart, one piece at a time and putting it back into the box.  Total time:  10 minutes.

Yep, they're puzzles, these boys of mine.