Smidders, those are very, very nice! I really like them. There are lots of nice things I could point out, but probably the one feature that immediately grabbed me was your consistent use of the granular / sand texture on all of them. That ties them together very nicely.
BTW, realize that the above high complements are coming from someone that is just about as far on the opposite end of the photographic spectrum as you can get. I have lots of photographic images that have been in wide circulation (glossy corporate brochures), exhibited, currently hung in local offices as decorative wall art, used in advertising, etc. but almost every one of mine is highly conventional / representational photography. For my own enjoyment, I do abstract compositions, but they don't sell and are of little interest in the circles I travel.
Again, GREAT job!
Tom M