Analogous to a snow avalanche on a steep mountain slope, an incoming light pulse initially frees just a few charge carriers which in turn free others until the original signal is amplified many times.

Berea College in Kentucky offers laptops to all of its incoming students. And if your computer breaks during matriculation, the university will repair it free of charge.

Fake calls is an application which with you can fake incoming phone calls, no actual call is made thus the calls are free of charge.