I wrote the text version of a game called Virus 3, which can be found here: http://www.arcadetown.com/virus3/gameonline.asp
The only differences are: the colours are indicated by numbers, the board is rectangular, and there is no limitation as to the # of moves (there is no "game over"). Also, unlike the online game, the score will be calculated by summing the square of the number of new tiles on the virus.
I want to find a way to maximize the score when the computer plays the game. Would you care to give me some ideas?