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Semaphore
Mechanical apparatus used to send messages / From Wikipedia, the free encyclopedia
For other uses, see Semaphore (disambiguation).
Semaphore (lit. 'apparatus for signalling'; from Ancient Greek σῆμα (sêma) 'mark, sign, token', and Greek -φόρος (-phóros) 'bearer, carrier')[1] is the use of an apparatus to create a visual signal transmitted over distance.[2][3] A semaphore can be performed with devices including: fire, lights, flags, sunlight, and moving arms.[2][3][4] Semaphores can be used for telegraphy when arranged in visually connected networks, or for traffic signalling such as in railway systems, or traffic lights in cities.[5]
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