And so we produce the following two fragments with these two sticky ends. So what do we mean by a two fold rotational symmetry? So, what we mean by that is if we take this molecule and we rotate it first about the x axis, 180 degrees, and then about the Y axis, also by 180 degrees. So if we make the two types of rotations, a two full rotation, then at the end we will produce that same molecule. So to see what we mean, let's actually conduct our rotation. So we make the cleavage.