...the dark matter SIGNAL found
in sodium-iodide crystals by the Italians.
The Big Bang Theory Season 2, Episode 15
When Mance gives the SIGNAL
and we hit Castle Black,
Game of Thrones Season 3, Episode 7
And we can just send up
a SIGNAL flare.
Breaking Bad Season 2, Episode 9
-perhaps we could come up with a SIGNAL!
The Big Bang Theory Season 10, Episode 16
How will we see your SIGNAL?
Game of Thrones Season 3, Episode 3