The gilded medieval domes of Moscow's Cathedral of the Annunciation rise over the Kremlin's walls against a brilliant blue sky tinged with feathery clouds. Early morning light softly burnishes them with light and shadow, causing them to seem as if they are rising out of the picture toward us, as well. Within just a few hours, when the sun moves higher in the sky, these same domes will appear flat and harsh. The angle of light is critical to both effect and meaning -- the lower the sun, the greater dimensionality.