Mirrors can be set up so that they reflect the lights from the sun or another bright source at people from other tables in an exam hall. That way when someone tries to see what another person is writing, the person's eyes get irritated.
An alternative method can use LED lights that are changing colors. the LEDs are covered by a small shade that protects the range that the person sitting on the table's face will see. When he looks away other people's LEDs irritate his eyes. The invigilators can wear protective glasses while going around the examination center or they can just monitor the whole place with a system of cameras and mirrors from afar.
The system of LEDs or mirrors can be used with a sound scrambler to make communication more difficult between the exam candidates. The sound scramblers can be made of a system of microphones and speakers. the microphones sense sound while the speakers try to cancel the sounds recorded in part or in full to prevent communication. Some of the "uncancelled" noise can be amplified so that anyone who talks will have the invigilator's attention. The noise cancellation can also be used to make the exam venue quieter when it is located in a noisy environment. The sound scramblers will be temporarily turned off whenever the invigilators want to turn make announcements.
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