In a lecture in 1997, Nathan Myhrvold, who was once Bill Gates’s chief technology officer, set out his Four Laws of Software. 1: software is like a gas – it expands to fill its container. 2: software grows until it is limited by Moore’s law. 3: software growth makes Moore’s law possible – people buy new hardware because the software requires it. And, finally, 4: software is only limited by human ambition and expectation.