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Cette catégorie comprend les 2 sous-catégories suivantes.
Cette catégorie contient les 21 pages suivantes.
1. Origami – 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. Avion de papier – 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
3. Cocotte en papier (jeu) – A fortune teller is a form of origami used in childrens games. Parts of the fortune teller are labelled with colours or numbers that serve as options for a player to choose from, the person operating the fortune teller manipulates the device based on the choices made by the player, and finally one of the hidden messages is revealed. These messages may purport to answer questions or they may be activities that the player must perform, the four corners of the square are folded into the center, forming a shape known in origami terminology as a blintz base or cushion fold. The resulting smaller square is turned over, and the four corners are folded in a second time, all four corners are folded up so that the points meet in the middle, and the player works their fingers into the pockets of paper in each of the four corners. Manipulations are done by various methods, for example, The player asks a question of the person holding the fortune teller. The holder then asks for a number or color, once the number or color is chosen, the holder uses their fingers to switch between the two groups of colors and numbers inside the fortune teller. The holder switches these positions a number of times, which may be determined by the number of letters in the color selected, once the holder has finished switching the positions of the fortune teller, the player chooses one of the flaps revealed. These flaps often have colors or numbers on them, the holder then lifts the flap and reveals the fortune underneath. Steps may be repeated to suit the users, as well as being used to tell fortunes, these shapes may be used as a pincer to play-act catching insects such as lice, hence the cootie catcher name. The salt cellar name refers to a different use for the shape, in which it stands on a table with the four points downwards. This shape was introduced to the English-speaking world under the salt cellar in the 1928 origami book Fun with Paper Folding by Murray. The use of paper fortune tellers in England has been recorded since the 1950s. Although the phrase cootie catcher has been used with meanings in the U. S. for much longer. Cootie Catcher, PBS Kids How to Make a Cootie Catcher
4. Grue en papier – 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
5. Kusudama – The Japanese kusudama is a paper model that is usually created by sewing multiple identical pyramidal units together through their points to form a spherical shape. Alternately the individual components may be glued together, occasionally, a tassel is attached to the bottom for decoration. Kusudama originate from ancient Japanese culture, where they were used for incense and potpourri, the word itself is a combination of two Japanese words kusuri, Medicine, and tama, Ball. They are now used as decorations, or as gifts. The kusudama is important in origami particularly as a precursor to the modular origami genre and it is often confused with modular origami, but is not such because the units are strung or pasted together, instead of folded together as most modular construction are made. Modern origami masters such as Tomoko Fuse have created new designs that are entirely assembled without cutting. The few good Kusudams with diagrams
6. Légende des mille grues – 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
7. Mathématiques des origamis – 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
8. Pliage de Miura – The Miura fold is a method of folding a flat surface such as a sheet of paper into a smaller area. The fold is named for its inventor, Japanese astrophysicist Koryo Miura, the crease patterns of the Miura fold form a tessellation of the surface by parallelograms. In one direction, the creases lie along straight lines, with each parallelogram forming the mirror reflection of its neighbor across each crease, in the other direction, the creases zigzag, and each parallelogram is the translation of its neighbor across the crease. Each of the paths of creases consists solely of mountain folds or of valley folds. Each of the paths of creases alternates between mountain and valley folds. The Miura fold is a form of origami, meaning that the fold can be carried out by a continuous motion in which, at each step. This property allows it to be used to fold surfaces made of rigid materials, for instance, large solar panel arrays for space satellites in the Japanese space program have been Miura folded before launch and then spread out in space. A folded Miura fold can be packed into a compact shape, folded material can be unpacked in one motion by pulling on its opposite ends, and likewise folded by pushing the two ends together. In the solar array application, this property reduces the number of required to unfold this shape, reducing weight. The 1996 Space Flyer Unit deployed the 2D Array from a Miura folded configuration, other potential applications of this fold include surgical devices such as stents and flat-foldable furniture
9. Origami modulaire – These insertions create tension or friction that holds the model together. Modular origami can be classified as a sub-set of multi-piece origami, since the rule of restriction to one sheet of paper is abandoned. However, all the rules of origami still apply, so the use of glue, thread. There is a misconception that treats all multi-piece origami as modular. More than one type of module can still be used, typically this means using separate linking units hidden from sight to hold parts of the construction together. Any other usage is generally frowned upon, the first historical evidence for a modular kirigami design comes from a Japanese book by Hayato Ohoka published in 1734 called Ranma Zushiki. It contains a print that shows a group of traditional origami models, the cube is pictured twice and is identified in the accompanying text as a tamatebako, or a magic treasure chest. Isao Hondas World of Origami appears to have the same model, the six modules required for this design were developed from the traditional Japanese paperfold commonly known as the Menko. Each module forms one face of the finished cube, there are several other traditional Japanese modular designs, including balls of folded paper flowers known as kusudama, or medicine balls. These designs are not integrated and are strung together with thread. The term kusudama is sometimes, rather inaccurately, used to describe any three-dimensional modular origami structure resembling a ball, there are also a few modular designs in the Chinese paperfolding tradition, notably the Pagoda and the Lotus made from Joss paper. The 1970s saw a period of interest and development in modular origami as its own distinct field. Since then the modular origami technique has been popularized and developed extensively, notable modular paperfolders include Robert Neale, Mitsonobu Sonobe, Tomoko Fuse, Kunihiko Kasahara, Tom Hull, Heinz Strobl and Ekaterina Lukasheva. Modular origami forms may be flat or three-dimensional, flat forms are usually polygons, stars, rotors, and rings. Three-dimensional forms tend to be regular polyhedra or tessellations of simple polyhedra, Modular origami techniques can be used to create lidded boxes which are not only beautiful but also useful as containers for gifts. Many examples of such boxes are shown in Fabulous Origami Boxes by Tomoko Fuse, there are some modular origami that are approximations of fractals, such as Mengers sponge. Macro-modular origami is a form of origami in which finished assemblies are themselves used as the building blocks to create larger integrated structures. Such structures are described in Tomoko Fuses book Unit Origami-Multidimensional Transformations, Robert Neale developed a system to model equilateral polyhedra based on a module with variable vertex angles
10. Monument de la paix des enfants – The Childrens Peace Monument is a monument for peace to commemorate Sadako Sasaki and the thousands of child victims of the atomic bombing of Hiroshima. This monument is located in Hiroshima, Japan, Sadako Sasaki, a young girl, died of leukemia from radiation of the atomic bomb dropped on Hiroshima on 6 August 1945. The monument is located in Hiroshima Peace Memorial Park in Hiroshima, the statue was unveiled on 5 May 1958, the Japanese Childrens Day holiday. Sadako Sasaki, who died of an atomic bomb disease radiation poisoning is immortalized at the top of the statue, shortly before she passed, she had a vision to create a thousand cranes. Japanese tradition says that if one creates a thousand cranes, they are granted one wish, sadakos wish was to have a world without nuclear weapons. Thousands of origami cranes from all over the world are offered around the monument, however, an exhibit which appeared in the Hiroshima Peace Memorial Museum stated that by the end of August 1955, Sadako had achieved her goal and continued to fold more cranes. Unfortunately, her wish was not granted and she died of the leukemia on October 25,1955 and her main reason of death was from the radiation poisoning from the atomic bomb Little Boy. Beneath the main structure lies a bronze crane that works as a chime when pushed against a traditional peace bell from which it is suspended. The two pieces were donated by Nobel Prize winner, Hideki Yukawa, today, people all around the world have the opportunity to donate cranes that they have folded in honor of Sadako and the others. The paper crane is a symbol of peace, which was her last dying wish, global Ministries - Fold Paper Cranes in Honor of Sadako. Http, //www. city. hiroshima. lg. jp/www/contents/1110438305305/index. html The Childrens Peace Monument Paper Cranes and the Childrens Peace Monument