split stitch
Ideally you would want to use an even number of threads for this stitch. I used two strands here.
Make a back stitch then bring your needle up half way along the stitch, coming up through the stitch itself (between the two threads) as in picture 1
Now bring your needle back down a stitch length along as in picture 2
Bring your needle back up through the stitch you have just made (about half way along) and continue in this way
I love split stitch as a filler stitch, especially for hair. It has a lovely texture. It’s also great for stitched hand writing.
Try to keep your stitches even and try it out with 4 or 6 threads to see the different effects.