From the pattern description: Ribs in varying widths make an elegantly textured surface of vertical lines through the interchange of the raised, smooth knit and recessed, lumpy purl stitches on one side. Changing the width of the ribs produces an interesting graded effect. The pronounced lines created where the knit stitches stand proud from the purl stitches can be softened by using lustrous, hairy mohair yarn or emphasized by using a smooth, crisp cotton yarn. The buttons are an important element so choose them in an interesting material, color and shape that complements the yarn. These pewter-finish buttons are sixteenth-century reproductions.