alternate back and fill bob bobble careen change chop and change coggle dangle dither ebb and flow equivocate flounder flutter go through phases intermit lack regularity librate lurch nutate oscillate pendulate pitch recur reel resonate return reverse ring the changes rock roll seesaw shake shift shilly-shally shuffle stagger swag sway swing teeter teeter-totter tergiversate toss totter turn vacillate vary vibrate wag waggle wave waver wax and wane wobble