[math-fun] Symbol for rotation?

I wonder if there is a standard symbol in math or physics or another field for one rotation. (Of course this is 2pi radians, but for certain purposes it would be more convenient to refer solely to the number of rotations, not radians.) If there is no standard symbol for this, I propose a circle with a dot in the center. Comments? --Dan ________________________________________________________________________________________ "Outside of a dog, a book is man's best friend. Inside of a dog, it's too dark to read." --Groucho Marx