Some stellar explosions, called gamma-ray bursters, are especially dangerous because all their lethal rays are focused into a narrow beam, like a searchlight.

It fired a narrow beam of light at the ground which tracked backwards and forwards as if it were looking for something.

To keep from rousing other sleepers, the device uses a set of parametric speakers capable of focusing sound into a narrow beam.

Focusing on the narrow beam of light they provide can cause a sort of tunnel vision that can trigger feelings of nausea in those prone to motion sickness.

The sun cast a narrow beam like a flashlight moving over a table as it traced flat circles that varied over the 365-day cycles.