First, let me tell two stories.The first one is one Japan soap factory had a problem that they sometimes shipped empty boxes to the customer without soap inside. So they spend much time and money to invent a X-ray machine to check whether the soap box is empty.The same thing happens in a small factory which doesn't have too much money. The solution of them to solve this problem is they use a desk fan to blow the empty boxes out of the belt and into a bin.The second story is NASA finds that in space with 0 gravity, astronauts cannot use pen to write. So they spend much money on developing a pen...