After you brush your wax, if you ran the back of your fingernail on the base of your board it would feel corrugated I guess you could say. Depending on the pattern of the structure, of course. Even a fine structure you can feel from my limited experience.
I wouldn't use this method though, I tend to be quite protective of my fingernails.
Just occurred to me. @barryj do you brush after waxing? I'm just assuming you hot wax, which I might be wrong about.