Yes, grainy texture does the trick. Reminds me an experience I had
trading piano lessons for chess lessons with a friend
who was a strong master. He asked me "what do you
call all of the E flats at the top of the second page of
Beethoven's Appassionata?" I said the term is ostinato,
but you could also say all the E flats at the top of the
second page. A while back you had this fantastic post
on Breguet rotors. There was one you called the Nautilus,
and then it struck me, yes, of course - looks like waves.