An old puzzle asks how a barometer can be used to measure the height of a
building. Answers range from dropping the instrument from the top and
measuring the time of its fall to giving it to the building's
superintendent in return for a look at the plans. A modern version of the
puzzle asks how a personal computer can balance a checkbook. An elegant
solution is to sell the machine and deposit the money.
-- Jon Bentley
How many
light bulbs
-- does it take to change a light bulb?
One, if it knows its own Goedel number.
Note: A Goedel Number is one of several ways to encode a
Turing Machine, the classical abstraction of a computer,
or for that matter of any algorithm....