[These pages were authored by the late Thoki Yenn, and were restored here from the Internet Archive by Erik Demaine, with contributions of missing files from various readers (notably Tommy Stevens, Roberto Morassi, and Boaz Shuval). If you spot any other bugs like missing images or pages, please report them.]

The Sacred Cut

Where the diagonal in the square cuts the elongated base line is the so-called sacred cut. This is the basis of the silver rectangle, and the A-format, it is also the point that indicates the doubling of the square.	The diagonal in a square has the lenght of 1: Ö2 , which means that it is the root of a square which is the original square times two. This is the anciant way to double the square.
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