braiding story lines

While I was away, I took the time to catch up on lots of issues of Writer's Digest. One of the articles I read talked about how, when writing a novel,you need three stories lines that run throughout the book. These story lines should be interwoven, just like the strands of a braid.

I found that to be a useful concept when thinking about my novel. I decided that the three story lines are:
1- What happened to Carrie (the main character's sister) that made her commit suicide.
2- Emily (main character) and David's relationship. Will they open up to one another and take a chance on love?
3- The sisters' family and early life, and the current relationships Emily has with her parents(or lack thereof).

Anyway, this video also reminded me of the idea of braiding, though it only uses two strands, and it's more of a study in contrasts and similarities than a true interweaving. In any case, I think it will be helpful to those of us thinking about story telling. And it's funny and about the Red Sox to boot.