Human beings have produced some remarkable machines in the past hundred years or so. The airplane, the automobile, and the computer are just a few examples of machines invented by ordinary people that have forever changed our lives. But if you want to see a machine that is more complex, more beautiful, and more unique than any of these, look in the mirror. Our bodies are capable of things that no machine will ever be able to accomplish, no matter how powerful computers get. As we wrap this book up, let's take a look at some of the wonderful things human bodies can do.