Poor Man's Bubbles

The sun was shining through the transom window in the office this afternoon.  Hawkins had been wrestling with a couch pillow.  He carried it into the office and body slammed it on the floor.  Shortly after, he says, "Bubbles!"  And began giggling and playing with what looked to me like imaginary bubbles.  I thought he was losing his mind.  "Bubbles, bubbles!"  He continues to exclaim in the most joyous voice as he dances around the room.  It wasn't until he hit the pillow again and again shouted, "Bubbles!" that I realized he was referring to the reflecting dust particles in the sunlight.