Letter A (Flag Semaphore)
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This shape represents the Letter A (Flag Semaphore) and the Number 1 (Flag Semaphore).
The presumed signals are letters. The signaller must use the ‘Numerals (Numbers to Follow)’ signal to indicate the next signal should be interpreted as a number. The signaller uses the Letter J (Flag Semaphore)–Letters to Follow–to revert to letters.