A mathematician, like a painter or a poet, is a maker of patterns... The mathematician's patterns, like the painter's or the poet's, must be beautiful; the ideas, like the colours 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. -G.H. Hardy

It seems that if one is working from the point of view of getting beauty into one's equation, and if one has really a sound insight, one is on a sure line of progress. - P.A.M. Dirac