There is no such thing as a new idea. It is impossible. We simply take a lot of old ideas and put them into a sort of mental kaleidoscope. We give them a turn and they make new and curious combinations. We keep on turning and making new combinations indefinitely
 but they are the same old pieces of colored glass that have been in use through all the ages.
Mark Twain, Mark Twain's Own Autobiography: The Chapters from the North American Review