Matt set the lamp to flash once every five seconds so the battery would last a long time.

Then out of the watery mist came a low call and a light flashed once, twice, three times.

The screen flashed once, and a direct visual communications feed began.

He sat up in his chair, his eyes flashing once.

The morning sun in the east flashed once in his eyes, and then he was through it, heading south.

His red hair flashed once above the surface and was gone.

His eyes flashed once with the fire of The Shadow.

Result: a tiny circle which flashed once and was gone almost before the eye could catch it.

Then light flashed once and I wasn't ready for it because it didn't come from the sky.

Doyle touched the side of the mirror, and the glass flashed once with light, then cleared.