These are locally collected rocks set in place for sitting or whatever. They are the top surface saved by a billion year old covering with dust event preserving the draiinage pattern from one day a billion years ago. Stuff was still the same back then. The water's surface would look the same as today.
There is the third photo that i have not seen very much or have not noticed very often. It appears to have formed as a wave pattern, but i don't actually know what the water that formed it was doing when it happened. Maybe it was tremor related with volcanic dusting that did it. Or possible it was made with extremely fine sand and slow moving water. Or maybe someone else has some ideal
hypnofan35 4 months ago