A novice was trying to fix a broken Lisp machine by turning the power off and on...

A novice was trying to fix a broken Lisp machine by turning the power off and on. Knight, seeing what the student was doing spoke sternly – “You can not fix a machine by just power-cycling it with no understanding of what is going wrong.”

Knight turned the machine off and on.

The machine worked. [http://planetvermont.com/v9n2/machine.html]