A diagram is the artifact used to show a graphical view of one or more elements of a model. Sometime designer whish to have slightly different views of the same model element: to show variation points, to explore alternatives, to highlight some details, to add stereotypes or comments ... In actual tools, each view is shown in its own diagram, realized by copying a based diagram and adding the modifications. Each time you modify the base diagram, you have to modify all copies. We propose to introduce in diagram the notion of layers, similar to layers found in graphical tools (like Gimp). A layer is a kind of slide showing some graphics. Layers are stacked one over the others. The resulting diagram is the sum of its visible layers. This proposal enable multiple views in one single diagram. The proposed solution allows doing much more things discussed in this article.