Curved piecing uses fabric pieces cut in circles or curves as part of quilt blocks or as the blocks themselves. Curved pieces can be concave (with the curve cut into the fabric) or convex (the fabric cut with a curved edge, as in a circle). Curved piecing is a component of many advanced or traditional quilts and can be used to create starbursts, fans, clamshells, and many other patterns. A rotary cutter and a curved piecing foot may be used to make curved piecing projects easier.