BaGua means "8 trigrams" there is a martial art by the name which means "8 trigrams boxing". The trigrams are the same as the ones that are used in the I Ching they have a significance in Taoism.

They consist of three(tri) broken or unbroken lines and there is a trigram for every permutation that can be formed with these two lines.

some examples:
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and
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When two trigrams are put together they form the hexagrams in the I Ching. Each trigram has a name, but I don't know them off the top of my head (and I am at work right now).

The Ba Gua Mirror is an octagonal wooden panel with a round mirror in the centre and the 8 trigrams around the edges. This may be difficult to imagine, but it's like the flag of Korea.