PATIO STITCH:
You can begin this stitch with the "white" center stitches. Depending on the color of your patio or flooring this will determine the color thread. I would look into a subtle over dye thread to compliment the patio.
With the "gray" stitches I would use a thread that blends in from the over dye. Filling in this section last.
Remember you can always use one color thread is you like.
Repeat pattern. Enjoy!