1.
Origami
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Origami is the art of paper folding, which is often associated with Japanese culture. In modern usage, the word origami is used as a term for all folding practices. The goal is to transform a flat square of paper into a finished sculpture through folding and sculpting techniques. Modern origami practitioners generally discourage the use of cuts, glue, Origami folders often use the Japanese word kirigami to refer to designs which use cuts, although cutting is more characteristic of Chinese papercrafts. The small number of basic origami folds can be combined in a variety of ways to make intricate designs, the best-known origami model is the Japanese paper crane. In general, these begin with a square sheet of paper whose sides may be of different colors, prints. Traditional Japanese origami, which has been practiced since the Edo period, has often been less strict about these conventions, the principles of origami are also used in stents, packaging and other engineering applications. Distinct paperfolding traditions arose in Europe, China, and Japan which have been well-documented by historians and these seem to have been mostly separate traditions, until the 20th century. In China, traditional funerals include the burning of folded paper. The practice of burning paper representations instead of wood or clay replicas dates from the Sung Dynasty. In Japan, the earliest unambiguous reference to a model is in a short poem by Ihara Saikaku in 1680 which mentions a traditional butterfly design used during Shinto weddings. Folding filled some ceremonial functions in Edo period Japanese culture, noshi were attached to gifts and this developed into a form of entertainment, the first two instructional books published in Japan are clearly recreational. In Europe, there was a genre of napkin-folding, which flourished during the 17th and 18th centuries. When Japan opened its borders in the 1860s, as part of a strategy, they imported Froebels Kindergarten system—and with it. This included the ban on cuts, and the shape of a bicolored square. These ideas, and some of the European folding repertoire, were integrated into the Japanese tradition, before this, traditional Japanese sources use a variety of starting shapes, often had cuts, and if they had color or markings, these were added after the model was folded. In the early 1900s, Akira Yoshizawa, Kosho Uchiyama, Akira Yoshizawa in particular was responsible for a number of innovations, such as wet-folding and the Yoshizawa–Randlett diagramming system, and his work inspired a renaissance of the art form. During the 1980s a number of folders started systematically studying the properties of folded forms

2.
Légende des mille grues
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Thousand Cranes Thousand Origami Cranes is a group of one thousand origami paper cranes held together by strings. An ancient Japanese legend promises that anyone who folds a thousand cranes will be granted a wish by the gods. Some stories believe you are granted happiness and eternal good luck, instead of just one wish and this makes them popular gifts for special friends and family. The crane in Japan is one of the mystical or holy creatures and is said to live for a thousand years, That is why 1000 cranes are made, one for each year. In some stories it is believed that the 1000 cranes must be completed one year. Cranes that are made by person and given away to another arent included. A thousand paper cranes are given as a wedding gift by the father. They can also be given to a new baby for long life, hanging them in ones home is thought to be a powerfully lucky and benevolent charm. Several temples, including some in Tokyo and Hiroshima, have eternal flames for world peace, at these temples, school groups or individuals often donate senbazuru to add to the prayer for peace. The cranes are left exposed to the elements, slowly dissolving and becoming tattered as the wish is released, in this way they are related to the prayer flags of India and Tibet. The Japanese space agency JAXA used folding 1000 cranes as one of the tests for its potential astronauts. There is a statue of Sadako holding a crane in Hiroshima Peace Park, and every year on Obon day, people leave cranes at the statue in memory of the departed spirits of their ancestors. Sets of origami paper are sold widely in Japan, with senbazuru sets including 1000 sheets of paper, string, commonly the cranes are assembled as 25 strings of 40 cranes each. The size of the paper does matter when assembling a thousand paper cranes. The most popular size for senbazuru is 7.5 by 7.5 centimetres, some people cut their own squares of paper from anything available, such as magazines, newspapers, notebooks, and printer paper. Origami paper used for senbazuru is usually of a solid color, larger size origami paper, usually 6x6 inches, often has traditional Japanese or flower designs, reminiscent of kimono patterns. Childrens Peace Monument Kunihiko Kasahara Sadako and the Thousand Paper Cranes Sadako Sasaki Orizuru

3.
Grue en papier
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The orizuru, or paper crane, is a design that is considered to be the most classic of all Japanese origami. It is a representation of the Japanese red-crowned crane that is referred to as the Honourable Lord Crane in Japanese culture, the Japanese culture believed that its wings carried souls up to paradise. It is often used as a wrapper or restaurant table decoration. A thousand orizuru strung together is called senbazuru, meaning thousand cranes, sadako and the Thousand Paper Cranes is a classic Japanese work that talks about the significance of a thousand paper cranes. It is said that a thousand cranes need to be made in order for a wish to come true, the resulting cranes are attached to one another or at the tip of the body. The trick is to all the cranes without breaking the small paper bridges that attach them to one another or, in some cases. Typical renzuru configurations include a circle of four or more cranes attached at the wing tips, if made from paper colored differently on each side, the cranes will be different colors. This origami technique was first illustrated in one of the oldest known origami books, media related to Origami crane at Wikimedia Commons Video showing how to make an orizuru

4.
Mathématiques des origamis
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The art of origami or paper folding has received a considerable amount of mathematical study. Fields of interest include a given paper models flat-foldability and the use of paper folds to solve mathematical equations, in 1893, Indian mathematician T. Sundara Rao published Geometric Exercises in Paper Folding which used paper folding to demonstrate proofs of geometrical constructions. This work was inspired by the use of origami in the kindergarten system and this book had an approximate trisection of angles and implied construction of a cube root was impossible. In 1936 Margharita P. Beloch showed that use of the Beloch fold, later used in the sixth of the Huzita–Hatori axioms, in 1949, R C Yeates book Geometric Methods described three allowed constructions corresponding to the first, second, and fifth of the Huzita–Hatori axioms. The axioms were discovered by Jacques Justin in 1989, but were overlooked until the first six were rediscovered by Humiaki Huzita in 1991. The first International Meeting of Origami Science and Technology was held in 1989 in Ferrara, the construction of origami models is sometimes shown as crease patterns. The major question about such crease patterns is whether a given crease pattern can be folded to a model, and if so, how to fold them. Related problems when the creases are orthogonal are called map folding problems, there are three mathematical rules for producing flat-foldable origami crease patterns, Maekawas theorem, at any vertex the number of valley and mountain folds always differ by two. It follows from this that every vertex has an number of creases. Kawasakis theorem, at any vertex, the sum of all the odd angles adds up to 180 degrees, a sheet can never penetrate a fold. Paper exhibits zero Gaussian curvature at all points on its surface, curved surfaces that cant be flattened can be produced using a non-folded crease in the paper, as is easily done with wet paper or a fingernail. Assigning a crease pattern mountain and valley folds in order to produce a model has been proven by Marshall Bern. Further references and technical results are discussed in Part II of Geometric Folding Algorithms, Paper fold strips can be constructed to solve equations up to degree 4. The Huzita–Hatori axioms are an important contribution to field of study. These describe what can be constructed using a sequence of creases with at most two point or line alignments at once, complete methods for solving all equations up to degree 4 by applying methods satisfying these axioms are discussed in detail in Geometric Origami. Methods for folding most regular polygons up to and including the regular 19-gon have been developed, the side of a square can be divided at an arbitrary rational fraction in a variety of ways. Hagas theorems say that a set of constructions can be used for such divisions. Surprisingly few folds are necessary to generate large odd fractions, for instance 1⁄5 can be generated with three folds, first halve a side, then use Hagas theorem twice to produce first 2⁄3 and then 1⁄5

5.
Avion de papier
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A paper plane, paper aeroplane, paper airplane, paper glider, paper dart or dart is a toy aircraft, usually a glider made out of folded paper or paperboard. Certainly, manufacture of paper on a widespread scale took place in China 500 BCE and it is impossible to ascertain where and in what form the first paper aircraft were constructed, or even the first paper planes form. The pioneers of powered flight have all studied paper model aircraft in order to design larger machines. Da Vinci wrote of the building of a plane out of parchment, and of testing some of his early ornithopter, an aircraft that flies by flapping wings. Thereafter, Sir George Cayley explored the performance of gliders in the late 19th century. The most significant use of models in aircraft designs were by the Wright brothers between 1899 and 1903, the date of the first powered flight from Kill Devil Hills. The Wrights used a tunnel to gain knowledge of the forces which could be used to control an aircraft in flight. They built numerous paper models, and tested them within their wind tunnel and their paper models were very important in the process of moving on to progressively larger models, kites, gliders and ultimately on to the powered Flyer. In this way, the model plane remains a very important key in the graduation from model to manned heavier-than-air flight. With time, many designers have improved and developed the paper model. One of the earliest known applied modern paper plane was in 1909 and he started to explain, in the course of it he picked up a paper menu and fashioned a small model airplane, without thinking where he was. It landed on the shirtfront of the French Minister of Education, much to the embarrassment of my sister, in 1930 Jack Northrop used paper planes as test models for larger aircraft. There have been many improvements, including velocity, lift, propulsion, style and fashion. Unmodified origami paper aircraft have very poor glide ratios, often not better than 7.5,1 depending on construction and materials. Modification of origami paper gliders can lead to marked improvements in performance, at the cost of weight. Often, increases in wing loading can encourage breakdown of laminar flow over a wing with a hybrid of origami, professors Ninomiya and Mathews developed more directed design strategies in the late 1960s and the 1980s. Previously, paper model aircraft had been designed without an emphasis on performance in flight, by using aerodynamic design, and fluid dynamics, both professors were able to design models that exceeded previous flight performance criteria by a very wide margin. Ranges of flight increased from the typical 10+ meters to 85+ meters, at present, the work of the two professors remains the last serious research work on improving the flight performance of paper model gliders