I am trying to figure out the proper name for upholstery stitching that is stitched in a "diamond" pattern. The only car I can think of for an example is the Carlsson CLS, which has it in the seats and on the door panels. Also, I believe I saw a Zonda with the same idea.

What's it called?

How difficult? Expensive? Anyone have it? Thoughts? Ugly, pretty?