[A little background: It had been a few months that I was searching for twin-blade cartridges for the Gillette SensorExcel safety razor that I prefer. I had almost given up on it by now, and was looking towards this seemingly inevitable upgrade to Mach3 or something when I suddenly hit a jackpot - I found a supermarket selling the make and model that I was looking for. I could finally purchase a year worth of supply. In other words, another year that I would effectively dodge Gillette Mach3 upgrade 'threat'.] The history goes that some hundred years ago, Mr. King Gillette was a wealthy but frustrated failure of an innovator at 40. He had written a book called " The Human Drift ", which argued that all industry should be taken over by a single corporation owned by the public, and that millions of Americans should live in a giant city called Metropolis powered by the Niagara Falls. His boss at the bottle cap company, meanwhile, had just one piece of advice: Invent somet