The object of virus is to keep as much of the board clean as possible. In other words, you must stop the virus (red squares) from spreading.
You can block the virus by placing tiles on the board. Each tile must be placed next to another of the same symbol or color. Empty tiles are wild. However, if you complete a full row or column, it will disappear and the virus will be able to get through. If you get stuck, press space to end the game.
Tips:
The virus always spreads from the last square infected if it can.
You can use the edges of the board to help box the virus in
