musical, part Dr. Seuss send up, Seussical (on stage at Parkway Playhouse from Thursday, July 28-Saturday, Aug. 6) is based loosely on Dr. Seuss' popular Horton Hears a Who and Horton Hatches the Egg . Characters from the Dr. Seuss repertoire, like the Grinch and Yerdle the Turtle, make a showing and the hi