Artificial Intelligence ............................
All the game has in terms of AI is the random number generator that picks the next
piece to enter the play-field. However, the game mechanics are such that this random
number is enough to completely change each game, presenting players with unique
challenges after every piece is dropped. Since the randomness ensures that players
never know what the next piece will be, they are forced to play the piece in a way that is
optimal for whatever one of the seven pieces comes along next. (Many incarnations of
Tetrisinclude a “next” feature, which shows players the next piece that will come onto
the play-field, a feature that does make the game a bit easier. Even when using this,
however, players still do not know what the next-next-piece will be, hence they are still
just making an educated guess as to where to stick the currently falling block.) If
gameplay is about opposition, meaning an opponent providing a challenge to which
players must react, and if in solitary computer games that opponent is the computer,
then the fact that a random number generator provides all the challenge inTetrisdem-
onstrates an important point. The AI the players face only needs to be as smart as the
game mechanics require. An AI needs to present players with a situation that will chal-
lenge them, and it really does not matter how the AI establishes that challenge. It could
be as complicated as the AI for a deep strategy game likeCivilization, or it could be as
simple as the random piece picker found inTetris. What matters is that the AI matches
up with the game mechanics to sufficiently challenge players.
The random nature in which pieces arrive at the top of the screen might suggest to
the reader that success atTetrisis just luck. If the pieces players get are random, how
can different players’ scores be compared against one another? The key point to realize
here is that, over time, the randomness of the pieces evens out. Just as die rolls in a
board game even out over the course of the game, the random pieces passed to players
inTetrisend up functioning as if they were not random at all. Since there are only seven
types of pieces, none with more than four blocks, and since players (at least initially)
have a large space in which to manipulate them, the randomness keeps the game from
Chapter 8: Game Analysis:Tetris 147
Tetrishas a very limited
artificial intelligence that
randomly picks the
blocks which fall into the
play-field. Despite its
simplicity, this AI
provides the perfect
challenge for the player.