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This helps deliver oxygen to the body and brain . A Hasse diagram consists of dots , which represent the elements of a set ; and connecting lines , which represent the relationships among the elements . the white and black players cooperate , becoming effectively a single player , " Erik Demaine explains . This bizarre , mind-bending object has no lip or edge and only one surface . " Coin collectors have a very developed language that describes not only the specific mint markings on a coin but also the grade of a coin , " explains Wood , who is himself a coin collector .