Note the lines of embroidery on the detail (above, right), particularly those on the blue in the lower right-hand corner.  This blue fabric started life as a solid color but became a plaid when I couldn't find exactly the right shade of blue plaid for the design.   The quilt has more embroidery, to change or enhance a color -- see the pink and the navy sections.  Some of the lines were added by machine, some hand-stitched.