Input (grade 5): On his own, Marshall created Happy Days, Laverne and Shirley (starring his sister Penny), and Mork & Mindy, which were produced by his associates Thomas L. Miller, Robert L. Boyett, and Edward K. Milkis.
Output (grade 12): He also created Laverne and Shirley (which co-starred his sister Penny) and Mork and Mindy (which starred Robin Williams) which were both spin-offs from Happy Days and just as successful and well-known.