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The universal recycling symbol ( or in Unicode) is an internationally recognized symbol used to designate recyclable materials. It is composed of three mutually chasing arrows that form a Möbius strip (an unending single-sided looped surface). In 1969 and early 1970, worldwide attention to environmental issues culminated in the first Earth Day. In response, then Chicago-based Container Corporation of America, a large producer of recycled paperboard which is now part of Smurfit-Stone Container, sponsored a contest for art and design students at high schools and colleges across the country to raise awareness of environmental issues. It was won by Gary Anderson, a 23-year-old college student at the University of Southern California, whose entry was the image now known as the universal recycling symbol. The symbol is not trademarked and is in the public domain. See reference (). The public-domain status of the symbol has been unsuccessfully challenged owing to its having become so widely used. ==Variants== The recycling symbol is in the public domain, and is not a trademark. The Container Corporation of America originally applied for a trademark on the design, but the application was challenged, and the corporation decided to abandon the claim.〔 As such, anyone may use or modify the recycling symbol, royalty-free. Though use of the symbol is regulated by law in some countries, countless variants of it exist worldwide. Anderson's original proposal had the arrows form a triangle standing on its tip—upside down compared with the versions most commonly seen today—but the CCA, in adopting Anderson's design, rotated it 60° to stand on its base instead.〔 Both Anderson's proposal and CCA's designs form a Möbius strip with ''one'' half-twist by having two of the arrows fold over each other, and one fold under, thereby canceling out one of the other folds. However, most variants of the symbol used today have all the arrows folding over themselves, producing a Möbius strip with ''three'' half-twists. Existing single half-twist variants of the logo do not generally agree on which of the arrows is the one to fold underneath. The logo is usually displayed with the arrows circulating clockwise, but the underlying Möbius strip exists in two topologically distinct mirror-image forms of opposite handedness. The American Paper Institute originally promoted four different variants of the recycling symbol for different purposes. The plain Möbius loop, either white with an outline or solid black, was to be used to indicate that a product was ''recyclable''. The other two variants had the Möbius loop inside a circle—either white on black or black on white—and were meant for products ''made of recycled materials'', with the white-on-black version to be used for 100% recycled fiber, and the black-on-white version for products containing both recycled and unrecycled fiber.〔 For example, a paper envelope might have both the first and last of these four symbols, to indicate that it was recyclable, and made from both recycled and unrecycled fibers. In addition to the resin identification codes 1–7 in the triangular recycling symbol, Unicode lists the following recycling symbols: * * * * (indicates product contains recycled paper) * (indicates product contains partially recycled paper) * (e.g. for acid-free paper) An ISO/IEC working group has researched and documented some of the variations of the recycling logo currently in use, and has made recommendations for adding some more of them to the Unicode standard. With the rapid expansion of materials converted to filament for 3-D printing from recyclebot technology a large expansion of resin identification codes has been proposed. 〔Emily J. Hunt, Chenlong Zhang, Nick Anzalone, Joshua M. Pearce, (Polymer recycling codes for distributed manufacturing with 3-D printers ), ''Resources, Conservation and Recycling'', 97, pp. 24-30 (2015). (open access )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Recycling symbol」の詳細全文を読む スポンサード リンク
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