Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Shaped canvases are paintings that depart from the normal flat, rectangular configuration. Canvases may be shaped by altering their contours, while retaining their flatness. An ancient, traditional example is the tondo, a painting on a round canvas: Raphael, as well as some other Renaissance painters, sometimes chose this format for madonna paintings. Alternatively, canvases may be altered by losing their flatness and assuming a three dimensional surface. Or, they can do both. That is, they can assume shapes other than rectangles, and also have surface features that are three dimensional. Arguably, changing the surface configuration of the painting transforms it into a sculpture. But shaped canvases are generally considered paintings.