At invisible signals they dropped into trees, then rose again to stream upwards, circle, and resettle.

He gave Omo an invisible signal to get the rest of his team into the room.

Was that a response to an invisible signal?

Not someone who tries to read people's invisible signals.

The psychologist had said each of the women was like an injured fish, sending off an invisible signal that inevitably drew the shark.

At some invisible, inaudible signal, the Micones lowered their triangular heads to the ground.

At Ekelund's invisible signal, the possessed were bringing out their hostages.

The cameraman made his invisible signals, and I pressed on through my forgotten script.

It was as though they were responding to some invisible signal.

The other waited as if for some invisible signal.