After I started working on this, I realized that my plan of attack for the knots was not going to work, and I went in a different direction. I will probably play around with the knot idea a bit more, but for this pillow, I ended up more of a woven lattice look. Even though it is really far from perfectly constructed, I like the way it turned out.
I started out with 2 17"x17" squares and 26 half inch wide strips of felt 23" long (this ended up being a bit longer than I needed, so you could probably cut your strips to be only 21 or 22 inches long).
I sewed all of the strips up along one edge of one of my squares. I found it easier to add the strips as I went along rather than pin them all to the square before sewing.
Next, I took every other strip and crossed it over the next strip. I sewed over the cross as I went along.
For the next line of stitching, I crossed same strip that went over in the previous row under the next strip.
I folded the strips at the ends of the rows back in the opposite direction like this:
And sew those suckers down:
I would cross all of the strips before sewing, but I would adjust them as I sewed along to make sure they were sewn at about the right distance from the previous line of stitches. If I were to do this pillow again, I would use chalk or a washable fabric pen to mark sewing lines at an equal distance (about 1.5 - 2 inches). This would give the lattice a much more regular look.
Here's what it looks like after a few rows of stitching:
Continue weaving the felt strips until you reach the end of the square. As I played around with this I found there are many different ways you can weave the strips to create different patterns and looks. Play around with it and see what you like.
The front of my pillow all finished:
Once the front is done, simply pin right sides together, sew three seams, flip right side out, stuff in form, pin final edge, and slip stitch shut as we did with the previous pillows.