A wonderful feature available in the Version 6 Bernina software is the ability to digitize squiggles. (Or stipple stitch as it is called in the software) You just outline the area that you want to fill, press the button and whola! You can adjust your squiggles to make them smaller and have a single, double or triple run of stitches.
Squiggles are a good background quilting design to have around an embroidered design. It flattens the background so that all attention is on the embroidery. The way that squiggles reflect light (in many different directions) is another contributing factor to have the attention moved from the background to the embroidery design.
Even so, it creates a lovely texture on the background- if one do nothing the blandness of the background would draw attention. Squiggles enhance the whole look without competing for attention with the main subject, the embroidery.
If you have the software go to the Bernina site and do this exercise. Experiment and learn how to use this wonderful optional feature. To get the best results, either embroider on the batting or add batting and a backing fabric before the squiggels are stitched.
This is just one of the FREE classes available at the Bernina website.