Having (finally) decided I was happy with the composition and the underlying structure of the zebra, it was time to start adding some detail or, rather, stripes. Having the stripes to follow the contours immediately creates a sense of form. And, conversely, flattens it out if you don't. Just compare the stripes on the neck with those on the stomach.
Again I found myself painting what I thought, not what my reference photos were showing me. I kept making the stripes identical in width, and parallel to one another. A zebra's stripes are far more varied. Time to stop and study the reference photos!
This is also the stage at which I added a glaze of Prussian blue in a few areas, especially the black stripes on the water's side of the zebra and, in an even thinner glaze, in the 'sky' area above the water. It's not dramatically blue, it just adds a subtle variation to the darks.