The shaders we have seen so far are quite simple and easily readable in the Node Editor window, but for several materials we'll see in this Cookbook, the node connections will be a lot more complex and confusing. One more aid we can use to improve the readability of these nodes are the frames. We can use them to visually organize the shaders' network.
Let's see the use of a frame with a simple shader that we already know:
Go to the Node Editor window and press Shift + A to add a Frame (press Shift + A and navigate to Layout | Frame). Move the mouse to place its arrow over the nodes, and notice that it always appears to be below them, as shown in the following screenshot:
Move the mouse cursor to a corner of the frame. It turns into a cross, which means that you can click and drag to resize the corners...