Observerare

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  Hwa Chatman

  https://inventmag.com/%EB%8F%9B%EB%8B%A8%EB%B0%B0-%EB%B3%B4%EC%A6%9D%EC%97%85%EC%B2%B4-%EC%B6%94%EC%B2%9C-%EC%9D%B4%EC%9C%A0-%EC%95%88%EC%A0%84%ED%95%9C-%EA%B2%8C%EC%9E%84%EC%9D%84-%EC%9C%84%ED%95%9C-%EC%A7%80%EB%A6%84/