[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.]

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 The Golden Rectangle
 To change a silver rectangle into a golden rectangle and by folding demonstrate the equation X=(sqr5-1)/2 1) Fold the short side over to lay along the long side, make a nick to mark the size of a square. fold the short side down to the mark, make a crease forming half a square. Put in the diagonal in this half square. 2) Fold the right edge over to the diagonal. According to Pythagoras, the diagonal in a half square is sqr5.. 3) Fold the upper left down to the diagonal, thereby deducting 1 from sqr5 and mark the place. 4) fold the right corner over to the mark, thereby dividing the rest of sqr5 in 2, and you have found X. as in------------ 5) Open all folds and study the creases. A4 format has been used in this example.
 updated 16. August 2000 FastCounter by bCentral