If the stairs are open on the side, then the carpet must be bent in two ways: lengthwise over the front of the stair, and widthwise over the side. In these cases, there is the possibility for smiling to occur on the side of the stair. To avoid sid smiling, look for a high-quality Berber with larger loops, which can help to cover the space between the rows when bent sideways. Higher qualities of Berbers will have less space between the rows.