that this image corresponds that label and you're trying to add a particular noise in the direction of the gradient of the output with respect to the input Society model starts producing some other label similarly here you want to make sure that the model the same squared learning model is regularized in the directions around which tomorrow on unlabeled data you want to make sure find directions in which the classifier is likely to be confused and you want to make sure that the model is not confused in those directions so that's the area