So the screw sense of our alpha helix basically describes the directionality of rotation about the axis of rotation for that particular alpha helix. Now, what do we mean by that? Well, if this is the axis of rotation, and if we look at the axis of rotation and we examine the directionality of that rotating alpha helix, the rotating polypeptide chain. In this case, it will point in the clockwise direction. So going this way is clockwise. And in this particular case, the screw sense of this alpha helix is clockwise.