Ice cake sides and background areas smooth in blue, wheels in white. Mark umbrella with toothpick, about 3 in. from cake edge. Outline umbrella and buggy with tip 3; fill in with tip 16 stars. Overpipe umbrella for dimension. For buggy, pipe tip 12 spiral outline handle; trim with tip 3 zigzag scallops, 5/8 in. deep and 1 1/2 in. wide. For wheels, pipe tip 5 outline spokes; add tip 12 outer rim and dot center (flatten and smooth with finger dipped in cornstarch). For baby, ice head smooth. Pipe tip 3 dot eyes, nose and cheeks; outline mouth and ears. Use tip 3 to outline and fill in shoulder area; position cookie head. Pipe tip 12 outline arm and umbrella handle. Use tip 5 to pipe dot hand over handle; pipe tip 3 dot fingers. Position bird cookie. Position additional heart drops on umbrella.