Occassionally an upholstery client may request two color double welt around the wood.
Here's sample of beige and black vinyl double welt (layed on a red table).  Making it can be pretty simple.

Making 2-Color Double Welt

First Cut your two strips of fabric about 1 1/2" wide.
Sew together, put your first color of welt into you sewing machine as if you were going to sew it as a single welt. Then put the second color face down on top of the first welt, and sew the two pieces together like this:

After sewing, trim the seam allowance on the back close to the seam:

Then wrap the second fabric around the next strip of cording and sew it together through the top:

After sewing, trim fabric close to the seam.