While I am working moving from machine top to bottom here on the machine, I am actually quilting a long ( 30+") horizontal area at the very bottom of this quilt. Machines are often 'happier ' going up and down as opposed to left and right... so I find it easy to work this way. I begin in the quilt middle point working outward toward one side. Starting from one far side and moving all the way across has more opportunity for 'wrinkle in the rug' surface distortion.
This is a interlocking ' earth strata' design begun with varied lengths of very slight 'S' curves. ( This is a great thread for this effort YLI Variations 35wt variegated every inch. Ever so slightly larger than my usual 40 wt choice... It works here and I love the very subtle variation of values/colors for this piece.
The varied lengths above allow subsequent efforts to 'interlock' with previously quilted areas. This is really a fairly relaxing fill pattern and goes pretty quickly. Remember to pause ever so slightly when making drastic direction changes. Doing so gives you a sharp point at the 'point' of direction change. Not doing so will often give you a sloppy or jerky stitch pattern at the turnaround point.