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The Banach–Tarski paradox is a theorem in set theoretic geometry which states that a solid ball in 3-dimensional space can be split into several non-overlapping pieces, which can then be put back together in a different way to yield two identical copies of the original ball. The reassembly process involves only moving the pieces around and rotating them, without changing their shape.
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The Petrucci Music Library is an internet-based collaborative music score library. You will find tens of thousands of scores composed by thousands of composers here, all available for free download.
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Uitstekende how-to.