The image in my mind was a 3-step-wave, a dark composition on white walls. So here it is!
In the very beginning, I wanted the painting to be dark enough to make a strong contrast with the foam(see whites only for the foam) and the rest of the painting. You know it is hard to paint when you work, trying to create time and all the duties. I think this was the reason that during the long process, the composition got darker and darker. So the image in my mind of the dark composition on white walls got stronger.
So here are the first three steps before it got that dark. The wave is much more visible, but I wanted the foam-the more little part of the painting to be the contrast maker.
These are the steps of one of the three canvases, the first one, the one on the left. You can literally see how it got darker in every step; and the grey-white foam was the last touch.
I colored to a flat color the background-the sky- at first. You can also see the general feature of the wave, drawn with a sketching pencil, a 2B probably, rough and simple.
Then I set the background color for the wave, which was light grey.
I added some curvy lines with thicker brushes, then with thinner brushes more of those curvy lines; some thicker, some thinner; some closer to straight, some archy etc.
The one in the middle, the wave is moving. You can see the steps are the same. Foam is not added in here yet.
The third wave. Four steps and more of them followed it.
So now some close-ups from finished versions:
The top of the first wave. I used a few hard brushes in different sizes.
Close-up to right down part
The up part of the wave from the third canvas
The middle part of the same wave, the third canvas
Down part of the same wave, from the third canvas and my signature on the right down part.

3-Step-Wave Oil Painting, 30×30 cm on canvas, three pieces.
If you are interested in the paintings, I am glad to share with you my Etsy shops link in here:
https://www.etsy.com/listing/630546327/3-step-wave-original-oil-painting?ref=shop_home_active_1