A man goes into a pet shop to buy a parrot. The shop owner points to three identical looking parrots on a perch and says “The parrot to the left costs 500 dollars”. “Why does the parrot cost so much?” the customer asks. The owner says “It knows how to use a computer.” The customer asks about the next parrot and is told “That one costs 1,000 dollars because it can do everything the other parrot can do plus it knows how to use the UNIX operating system.” Naturally, the increasingly startled man asks about the third parrot and is told “That one costs 2,000 dollars.” Needless to say this begs the question “What can it do?!” The owner replies “To be honest I have never seen it do a thing but the other two call him boss!”