no mass when traveling through a gravelling sheet. >> with marbles? >> these characters want to be included and there is the beautiful penny who lives across the hall from sheldon and leonard. >> oh, welcome to the building. >> oh, maybe we can have coffee sometimes. >> oh, great. >> great. >> she's funny but they show her as having a fraction of their iq. >> cal tech department, you are maybe familiar with some of my work. it is orbiting -- taking high resolution photographs but then they bring in bernadette and amy and suddenly there is a bunch of women and the show felt more balance. >> i am amy and you are cooper. >> she became sheldon's love interest and that opens up a