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出典:Wikipedia
出典:『Wikipedia』 (2011/05/16 07:51 UTC 版)
The Tetractys (greek Τετρακτύς) is a triangular figure consisting of ten points arranged in four rows: one, two, three, and four points in each row. As a mystical symbol, it was very important to the secret worship of the Pythagoreans.
Tetractys