Invalid signals include microwaves made by sources separate from the transmitter, such as radar jamming and deception.

These signals include the use of a finger wiggling signal called Twinkles to indicate agreement.

Such signals can include tugging an ear or raising a bidding paddle.

Other signals associated with hostility includes piloerection and tail lashing.

Physiological signals include a rapid heart rate and the shutdown of the digestive system.

At one point, the second signal included a high-intensity strobe embedded in the red signal; however, the strobe has since been removed.

'And the signals included details of the crime committed at Radnor Walk?'

These signals include facial expression, tone of voice, and posture.

Essential signals in the path to intimacy include facial nuzzles, kissing and caressing each other.

His signals included other countries, too, and he memorized those as well.