Stuxnet was a weapon, a kind of a smart bomb- perhaps one of the smartest bombs ever created. A bomb that couldn’t rely on operators, cameras, and laser targeting, instead it had to "think" it's way to its destination. An invisible commando unit dropped deep behind enemy lines. And its payload- not explosives, but lines of code. Part two of the three-part Stuxnet series explores how the first bits of code were weaponized.