"semaphore" . "signal flags" . . "semaphore flags" . . "passing signals" . "Signal" . "semaphore station" . . . "Flag semaphore systems" . . "semaphore-flag" . . "Flag semaphore" . "semaphores" . . . . "signaling" . "signalling" . "Flag_semaphore#Japanese_semaphore" . "semaphore towers" . "semaphore communication" . "semaphore-signal flags" . . "Semaphore" . . . "semaphoring" . . "semaphore flag signaling" . . "Signaling" . "semaphore code" . "semaphore flag" . "flag semaphore" . . "semaphoric" . "flags" . "Flag semaphore" . "two-arm semaphore" . "semaphore signals" . . . . "Semaphore flags" .