Our staff member, Judy, recommended the Giant Scotch Lattice as a great stitch for a background.  Looking at the graph you can see that 3 different threads or colors can be used.  Playing around with threads is always fun.  Try Gloriana or Splendor for the Scotch stitch.  Use metallic thread such as Kreinik, Neon Rays Plus, Silk Lame Braid or Entice for the Elongated Double Crosses.   You can match the metallic thread to the color of the Scotch stitches or you can go a shade lighter or darker.  For the blue line use a darker thread either in your colorway or a totally different color.