In the chess-like game Cosmic Blocks, by Narcissa Wright, and available through the Discord server at https://discordapp.com/invite/szpznUj , players each start
with a 1-square base on an 11-by-21 grid. That base spreads
influence, represented by coloured shading of squares, to the 3-by-3
area surrounding the base. The goal is to spread this influence into
the opposing base.

In each round of Cosmic Blocks each player selects a
block from their stockpile and a space on the grid to place the
block. Most of the blocks contain an arrow or multi directional
indicator both of which signify that any influence that spreads to
this space of the block also spreads in the direction indicated by
the block, at a distance of either one or two spaces.

In a round each player has 30 seconds
to select a block and a space to place it on and then both blocks are
placed at the same time. This means that each player has to guess
what block and space their opponent will select and so no player has
perfect information and therefore Cosmic Blocks is not a determined
game in which an unbeatable strategy exists for one player.

If two blocks are placed on the same
space in the same round a collision happens and the result is a dead
space which does not spread influence anywhere. A space can, however,
be under both players influence at once, as shown by a square that is
shaded with both players' colours. If the influence from both bases
reaches each other on the same round, the game is a draw.

At the moment, no computer player
exists for Cosmic Blocks. That's not surprising given the challenges
in developing such a program.

First the solution space is extremely
large, it is comparable in size to Go and is much larger than the
pollution space in chess. To get a sense of this, in Queen's chess
each player typically has 40 choices for any given move. A player in
Cosmic blocks typically has about 200 spaces to place one of 16 block
types, implying about 3200 choices for a given move, as well as 3200
choices for the opponent who is placing a block at the same time.
Without pruning, there are 10^24 possibilities after only 3 rounds.

Second, there is a rock-paper-scissors
aspect of simultaneous play. A computer player cannot simply employ
the minimax principle and assume an opponent will choose the best
response to a given move. This is because the opponent is not
responding to the move, they are playing at exactly the same time.

Instead a computer player needs to
estimate the probability that an opponent will choose a given space
as well. Because an opponent may also be estimating these
probabilities using heuristics, and playing accordingly can order
strategy should be employed to avoid being second-guessed.

The paths of influence from one base to
another can be simplified into three classes above the middle direct
and below the middle. Guessing the path that an opponent will develop
is one thing nature of that development which also needs to be
inferred. This combination of poker-style hidden information and a
large set of choices like Go offers the kind of strategical depth
that provides great difficulty for a computer player, as well as some
exciting opportunities.

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