Fold open edge of bag back 2 1/2", then fold it again to make a brim 2 1/2" wide (sketch a). Cut off bottom of bag. Gather cut end together and pull down through folded brim (sketch b). Put a rubber band tightly around gathered end about 6" from last fold. Cut off excess paper below rubber band. Push gathered ends back through folded brim to form top of hat (sketch c).