The polyptych by Marco Tirelli features a number of simple, monochrome pieces. A sense of both unity and subtle difference is produced by the tiny variations in light source placement and intensity found in each panel. The bright quality of the light is emphasized by the dark background, which invites viewers to reflect on the relationship between presence and absence as well as light and dark. The link between perception and reality is a recurring theme in Tirelli's art, and this polyptych is no exception. Our perception of what is actually solid and what is just an optical effect is challenged by the minute changes in light and shadow, which produce a sense of depth and illusion.