These are the treadles. The white cords are attached to the shafts, which hold the heddles.
And here is me pressing down on treadle number 1 and attempting to take a picture of the result, which is that several of the shafts are raised, thus raising the threads in a certain way. When I then put my weft yarn through those threads and let the treadle back down, part of the pattern is created.
So what I did when I was done with the first towel was to reorder which shafts are raised when I push on a treadle. My treadling order is still the same, so the only thing that's changed is which shafts are attached to which treadle. And this is the new pattern. I don't like it as much as the first, but it's growing on me.