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## Answers to 3D Tic-Tac-Toe

What are some ways in which you can force a win? Do you have an advantage as the first or second player?

Consider the following strategy: As the first player,
take the center of the middle board first. Whatever move the other
player makes, you can make a move that requires the other player to
block a 3-in-a-row in a place that cannot be in the same 3-in-a-row
as their first move. Then you can choose a spot which gives you two
possible 3-in-a-rows. Then the other player must block one but you
still win -- in a total of 7 moves.

For example,

- you move in the center (X)

- the other player moves anywhere (O)

- you move so that they have to block you where it won't give
them 2 in the same row

(This is possible since every space other than the center is not
a 3-in-a-row with some other space -- those around the outsides are not in a row with the center square in a different level and those in the center cannot be used in a 3-in-a-row except within the level since you already hold the center space.)

- the other player moves to block you

- you move to have two possible 3-in-a-rows

(This is possible since you had moved to have two in a row
earlier -- one of which was the center; and because of the three
levels you can move so you have two potential 3-in-a-rows, one within
a level and one using the center space.)

- the other player blocks you

- you win

Another interesting question to explore would be to find the expected length of a game if players are just playing randomly.