Original: 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 .
Simplified: 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 .