Chuck Lorre knows Penny was "one-dimensional" and "clichéd" in the early days of the hit sitcom, but after several episodes he realized "there was a brilliance" to her.Figuring out Kaley Cuoco's bubbly character Penny may have been more difficult than quantum physics for the guys behind The Big Bang Theory.

"We did the very clichéd, in the beginning, goofy blonde who says foolish things," Lorre says of the character Penny.

"The Big Bang Theory" co-creator Chuck Lorre says Kaley Cuoco's character Penny took a few seasons to fully understand. "It's a cliched character: the dumb blonde, and we missed it," Lorre said during the first episode of "The Official Big Bang Theory Podcast.