My sewing machine has lots of fancy stitches.
I have sewed one of the fancy stitches down the center of a piece of sashing. Then I added parallel rows of other fancy stitches, say one on each side, for instance.
The multiple rows of stitching make a new more complex design.
Practice, with some fabric strips in various colors and threads with different lines of fancy stitches just to see what happens!
If you use cornerstones, it makes the idea easier to use.