How would I go about fluting styrofoam balls? Is there a tool I can use to make indentations or is there maybe technique for putting tapered fondant or gumpaste "ropes" on the ball before covering them with fondant?
Why would you want to flute the styro? Are you trying to make a pumpkin?
To my way of thinking it would be much better, simpler, easier to make fondant ropes on the ball, then cover that w/fondant.
If you still would rather 'flute' the styro, I'd take something like a pencil and press it hard into the styro (from top to bottom) to indent it. If you have the right kind of styro it should work fine w/little mess (as opposed to carving it).