Laptop professionals must have good reasoning and logical drawback fixing skills, be observant, alert to element and tenacious in pursuing problems to completion. The US Army asked Bell Laboratories to design a machine to help in testing its M-9 gun director, a type of analog pc that goals large guns to their targets. Mathematician George Stibitz recommends utilizing a relay-based mostly calculator for the undertaking. The outcome was the Relay Interpolator, later known as the Bell Labs Mannequin II. The Relay Interpolator used 440 relays, and since it was programmable by paper tape, was used for other purposes following the struggle.