It's only been two weeks, but Comet has grown enormously. You can see some of the facial features he'll have as a grown dog: the high forehead, the squared muzzle, the clear eyes. He's already dramatically different than when we brought him home.
He's also developing more of an adult gait. It's still mostly a puppy's bounding around, but you can see the beginnings of a smooth, rolling gallop in there. I think he'll be quite the athlete.