Hello folks, Mr. Vincent Morgan mentions cording of a style he called
"diamond string".  I used to work in the toy industry so I know a bit
about cording, and it's actually called a "diamond braid" or "Maypole
braid" cord.

I found a couple of sources via an Internet search.  If these suppliers
won't sell to you directly, simply ask them for a distributor in your
area or the names of companies who buy the specific diameter you need
and contact them to sell you a small amount.  It's worth a try!
Here are the links to two suppliers/manufacturers:

  http://www.gpjohnson.thomasregister.com/olc/gpjohnson/
  http://www.rmcord.com/braid_types/

Sincerely,
Diane H Kay