to things like textures, contrast between two colors, or edges. These are the image analysis-equivalents of the letters used in our analogy. And as a CNN goes up in the hierarchy, it looks for combinations of these filters, getting more and more complex with each layer. As the complexity increases, the CNN gets closer to identifying what it's looking for. So the specific features analyzed at each layer help put the whole thing together. So, for example, some of the earlier work showed that some layers tend to be better