is used up, then a card from the tail should be put to fill in the space immediately. if all the cards in the tail are used up, then you can also fill in empty spaces in the wings by a card from the discard pile. when the stock pile are used up, you can turn over the discard pile to become the stock card and continue playing, you can turn over the discard pile twice in this game. when there are no more moves, the game is over. 