| Clue | Source | Date |
|---|---|---|
| Level crossing signal with a pendulum-like motion | The Telegraph General Knowledge | 01 May 2016 |
| Move to and fro | ||
| Send a signal by waving a flag | ||
| Signal by flapping | ||
| Move to and fro | ||
| Flag-signal motion | ||
| Signal code. | ||
| Signal with flags. | ||
| Navy communication system. | ||
| Art of semaphore. |