1. Sometimes in a top-down design, after the sweater is divided for the sleeves and body stitches are rejoined, the pattern stitch doesn't fit neatly into the new stitch count for the body. For example:
|Working down from the underarm of the Perth Cardi (right side)|
|Same as above, but from the wrong side|
2. A seam stitch allows shaping to occur neatly in a circular design when there is a pattern stitch. The shaping might be in the waist area, or it might be in the sleeves. In the case of sleeves, this is where you will need to use centred double decreases in purl (see my post for Apr.23, 2011).