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# How many combinations?

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How many combinations is possible for a 3x3 square grid, if the center square always is the same and the grid can be rotated 90, 180 and 270 degree but not fliped horizontaly or verticaly? Example: This one: x - - - C - - - - is the sam as: - - x - C - - - - - - - - C - - - x - - - - C - x - - But this is diffrent: - x x - C - - - - How many combinations viewed on the whole? I don´t know if I have every one and if I miss someone my BIG if-switch get fucked up!

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Because no-one seems to understand my question, here is a
picture of all combinations I can think of:

Can you find more combinations?

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I can''t really do this for you right now but you should write a short dos program that calculates this for you.

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Kylotan: It can´t be 256 combinations! You forget that I can rotate each square 90, 180 or 270 degree.

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Hum... 256 combinations, 4 angles... 256/4 = 64... Maybe I have found them all?

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You already made that diagram; that is exactly all the possible combinations. Make 3 copies of that diagram at 90'', 180'', and 270'' rotations, and you have every possible combination.

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OK, I know now (thanks to Kylotan) that it is 256 combinations,
but how much smaller can I make that number if I can rotate each square 90'', 180'' or 270 degree?

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There are 64 combinations, because the center square was ruled out and for all other squares there exists 4 symmetrical points (you can rotate them 4 times 90 degrees to come back to the original configuration).

I don''t know if the 64 you have found are the correct ones, but I think so. But anyway, there should be 64 combinations from which you can form all 256 combinations by using rotates of 90, 180 or 270 degrees.

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Thank you man!

That was all I wanted to know

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