30 years ago I started to play with multiple exposures for no other reason than the Minolta Autocord I had just purchased could do it. For the next 10 years I discovered many things about the use of multiple exposures; one discovery was that in an image of marlin grass and clouds made using multiple exposures on a windy day some areas of grass were rendered absolutely pin sharp after giving 14 exposures over a period of 10 minutes. The clouds and other areas of grass where blurred as I expected and had planned for. I found it hard to believe but regularly repeated this in the next few years.
I also noticed that the wind seems to take a particular course through a field of standing grass that can be identified by the areas of grass that are blurred next to grass that is sharp.