The japanese art of paper folding, which usually involves creating figures (animals are very popular) from an exactly square piece of paper. Some folders favour other shapes that they claim reflect a more perfect balance (or that just look cool / make certain figures easier), such as a golden ratio rectangle, or a hexagon or an octagon, but the square is the choice most of the time.

The acknowledged (living) master of origami is Akira Yoshizawa of japan, who is amazingly prodigious and is famous for his incredible anotomically accurate depictions of animals. He has authored hundreds of books, but they represent just a small fraction of the figures he has created. Of the western school, I'd say the most significant is Peter Engel, an american folder and the author of "Folding the universe", which has 20 or so lovely figures, including his amazing butterfly, and better still, half the book is devoted to an incredible far ranging and multidisciplinary essay on origami, exploring its links to mathematics, chaos theory, calligraphy, escher, oh, everything! Very hofstadter-esque in its brilliant making of connections and the sense of wonder he brings to his craft.

Some traditional origami figures involve painted faces or the use of cuts in the paper; most serious folders adhere to a sort of purism, insisting on using only one sheet and making no cuts, and relying on the creases to convey details instead of marking the paper. Some complex figures require enormous sheets of paper in order to complete all the folds without tearing the paper or necessitating folds too tiny for human hands to manage.

Overall, I find origami has a similar appeal to ansi art: not revered for the intrinsic beauty of the medium, but appealing for the challenge involved in finding expression within the severe limitations involved, which when successful lends an aura of awe and beauty inachievable in free-er media, like the stark but deeply touching beauty of an otherwise ordinary plant that manages to flourish in a bare desert plain. Mm.