I see people ask in particular for the "Star cards" for the game. I went through my grandson's cards and see that the first group all have star cards,, the middle 20 have left facing quarter moon and the last 20 have right sided quarter moon. why do people ask for a "star card"? Is this because the first 20 are harder to find or is there a particular series that is harder to find? I know that they had some cards with different cuts on the edges but I didn't know they had different series. anyone know?