It IS possible to wear him out

Today was an epic day for snow moving.  Marley did his flying dog snow catching for the whole back deck.  I was shoveling normal fell-from-the-sky snow, the fluffy stuff.  Then he did about a half hour of chasing snowballs and looking for them buried in the 2 feet or so of snow on the ground.

After lunch, half the back roof snow had come crashing down onto the deck so Tom & I went out and shoveled the deck again.  Again Marley did the flying, leaping, twisting to catch the shovelfuls of snow.  After I cleared the car we went to the post office and when we got back more of the roof snow had come down onto the deck and I had to dig a path to the house - I just didn't feel like shoveling the whole deck again.  At first Marley whined for the snow, but after a couple he just watched me closely without whining or barking.  By golly, he does have an energy limit!