I've been searching for ways to demonstrate the similarity of patterns in sand at the beach to the clouds above. Recent efforts finally produced a result I am happy with. Here is the image I stared with:
This required some cropping and adjustment in Camera Raw:
Among other changes the image was transformed using perspective. Then another copy of this was inverted. The black color was selected and filled with white. The inverse selection was filled with blue. Since horizons typically appear lighter than the sky above, a gradient was applied:
Similarly a gradient was applied to the sand colored half. The end result is: The sand seems to stretch off to a distant horizon. And its colored mirror image looks very much like clouds in a blue sky.