If you need a little bumpy line on your quilt top, try the Coral Stitch. The lines across the sky made with the Coral Stitch remind this curious bird of something out of geometry class. But, alas, that was 40 years ago and the little bird has discarded that info long ago along with the Pythagoras Theorem. (If you're out there Pythagoras, my apologies.)
Here's how I make my Coral Stitches: Bring the needle and thread up at point A and stretch the thread out on the fabric in a line to the left. At a distance of about 1/4" from A, take a small stitch from point B to C under the thread.
Snug the thread under the needle and then slowly draw the needle through point C to create a knot. Repeat these steps across the fabric. Somehow making this knotty little line feels so good!