"The two old men couldn't help smiling, but whereas Farder Coram's smile was a hesitant, rich, complicated expression that trembled across his face like sunlight chasing shadows on a windy March day, John Faa's smile was slow, human, plain, and kindly." - Phillip Pullman, The Golden Compass
Beyond the wonderfully precise simile, note the way that the sentence itself instances the comparison it's making. Look at how much weight is allotted to setting out Farder Coram's smile: It takes longer, it's more complex, many of the words are latinate, polysyllabic, abstract ("hesitant," "complicated," "expression") compared to those for John Faa, whose simpler smile is set out more plainly in shorter, simpler words. So that the sentence makes its comparison acoustically, almost tangibly, as well as visually, and intellectually, and gains force. (It's true that Farder Coram's smile is compared to something you might see and John Faa's is not, which troubles the point a little - but what you might see is hardly concrete. It's ephemeral, passing: light and dark.)