The mathematician's patterns, like the painter's or the poet's, must be beautiful, the ideas, like the colors or the words, must fit together in a harmonious way. Beauty is the first test; there is no permanent place in the world for ugly mathematics...It may be very hard to define mathematical beauty, but that is just as true of beauty of any kind-we may not know quite what we mean by a beautiful poem, but that does not prevent us from recognizing one when we read it.
- James F Peters
