The shamrocks are standard piecing. The stems are appliqued, or use green rickrack or another trim.
Designer Margie Ullery included two configurations in her tutorial. The square topper is 30″ x 30″. The runner is 12″ x 36″.
The scallops are made using the Quick Points Scallop Ruler S1. It allows you to make scallops in a continuous row instead of one by one.