Byzantine art preferred chameleonic materials such as gold, glass, jewels, and variegated marbles with which to make images and shape architectural space. When set in shifting diurnal light and the flicker of candles, the variegated surfaces of the icon and ecclesiastical interiors produced a spectacle of shifting appearances, or poikilia. Both before and after Iconoclasm, ekphrasis explicitly trained the viewer’s perception to interpret these phenomena as manifestations of the ephemeral dwelling of the metaphysical in matter. Focusing on three examples—the ambo and apse mosaics in Hagia Sophia and the portable icon of the Archangel—this essay explores how the perception of animation of the icons and architectural interior emerge out of the synergy among material images, imagined visions, and ekphrasis.