21.   The system uses infrared beams to scan the pavement and detect center line and roadside markings.

22.   Then she aims an infrared beam at a nearby printer, which makes a copy that the patient can take to the pharmacist.

23.   To recognize that someone wants to get in, the car senses a hand touching a handle by using capacitors, infrared beams or microswitches.

24.   Wave an arm anywhere in the path of its infrared beam, and it shuts up for eight minutes.

25.   You can check the reflectivity by firing an infrared beam through the skin at the mirror and measuring the reflected light.

26.   As it flung itself toward the cooling river it unwittingly tripped the infrared beam on a remote-controlled camera.

27.   Each camera sends out an infrared beam.

28.   It follows his eyes by shining an infrared beam on them, then measuring the angle as the beam reflects off his pupils when they look at a monitor.

29.   The microphone and device are linked by an infrared beam.

30.   These simple devices emit an infrared beam.