Yeah, shadows on the sky isn't really something you'll see in a real life situation.
But some kind of moving shadow on the trees might look good though. Anyone?
That would be tricky but not impossible.Hint : Flip the shadows rightside up and make them a bit smaller than the actual tree , Then As the sun moves the smaller shadows on the trees will move ever so slightly.Sounds easy enough , But how does one stop the shadow from moving all the way to the left or right?.This will make a great competition,The one with the most realistically looking shadow will be the winner.