Traditionally the wedges are pieced together to form a circle then appliqued to a square block of muslin. In order to do this you need to stop your piecing at least 1/8 _ 1/4 inch from the outside edge. This allows you to turn under at the seams. Some traditional blocks simply turn under the inside circle and applique to the background and others applique a circle on top of the center, usually yellow. Most of the old quilts I have seen have been assembled with sashing.