An entry in the 2015 18 Card PNP design contest by J. Ramón Palacios. Setup Shuffle and deal 8 cards to each player. Place the remaining card face up in the center of the table. The play area will be a 3x3 card grid, with that card at the center. The player who has been most recently sick chooses virus or leukocytes. The other player starts playing. The one with virus keeps the rules card as a reminder. Gameplay In turns, each player play 1 card face up on the play area, on a free space or completely overlapping another card. To overlap a card, the new card number must be higher than the overlapped card. At the end of the game 9 cards must be exposed. None of the 9 spaces must be left uncovered. So, for instance, if there are 3 free spaces in the play area and players have 3 cards in their hands (one player with 2 cards; the other, 1 card), no more cards can be overlapped. If there are no free spaces and you have a card whose number is lower than the numbers of the cards in the play area, that card is out of the game. The game ends when all the cards are played and the winner is the one with most virus or leukocytes on the board. In case of a tie, play again.