So undulation in Breaststroke is required. And the really easy simple answer is that it’s required to breathe. So every single stroke you pop your head out, you’re gonna take your breath, you have to undulate to get the head out of the water. So therefore when you swim Breaststroke, you must undulate. There are different amounts of undulation that you can do. So you don’t have to undulate to a certain extreme to get your head out, you could undulate very little and still get your head out of the water similarly to what we see in Butterfly. But with Breaststroke being a short-axis stroke, we hit hips, we pop the head up, which is the back extension, we get the head above the surface of the water and we take a breath.