Quilters sometimes sew fabric on top of a foundation. Foundations are used when the fabric (bias-cut fabric, knits, silks, velvet, and other specialty materials) in the quilt top is difficult to sew and keep straight. The foundation can be fabric or paper. Muslin works well as a foundation because it is cheap and does not have a pattern. Newspaper is a cheaper alternative. Beginners like sewing on a foundation because this helps with accuracy.