You know that the three sisters' last name is Halliwell. Well, in "I've got you under my skin" at the beginning during the credits, you are told that their father's name is Victor Halliwell. But, in "That 70's Episode", their mother who's name is Patty Halliell, and their grandmother named Penny Halliwell are talking. Penny says that Patty never took Victor's last name. But somehow, both Patty and Victor have the same last name, as do their three children. Makes you wonder...