Create Navigation Background CSS

I came upon this website today:

http://leaverou.me/2010/12/checkered-stripes-other-ba开发者_C百科ckground-patterns-with-css3-gradients/

and made me curious as to how you create the strip coming out from behind the white div without using images? If anyone can tell me, I'd surely appreciate it. Also, if someone doesn't understand what I mean, please let me know.

There are a lot of tutorials for making 3D Ribbons (as it's called). Example: http://www.pvmgarage.com/2010/01/how-to-create-depth-and-nice-3d-ribbons-only-using-css3/