https://www.beading-arts.com/2009/08/spiral-square-stitch.html

1. Leaving a 5 to 7 inch tail, string on two beads of color A and one bead of color B.    

 

2. Pass the needle and thread back through all 3 beads, and then a second time through only the two color A beads.  Pull the circle snug.

3. Add two color A and one more color B beads.  Pass the needle back through the previous color B bead and pull snug.

4. Pass the needle and thread forward through all four color A beads and pull snug.

5. Continue adding two color A beads and one color B beads for each stitch.  Each time, you will pass your needle back through the previous color B bead and forward through the final four color A beads.  The bead work will begin to circle, and then to spiral.  

6. Add as many stitches as needed to make your spiral the length you desire.

7. Add one more bead as a stopper bead, and pass your needle and thread back through all the color A beads, back to the beginning.

8. Now you will have both threads exiting one end, making it easy to stitch your spiral into place on the embroidery piece later.