Layers, Like Onions...

Layers, in a nutshell, are basically a way of fitting more visual elements into an area without expanding the area.  Layers create a dimensionality that allows images to lie on top of each other.  Any images that are covered carry a continuation through the image on top which conceptually allows the entire image underneath and hidden to exist in the viewpoint.
Layers also allow more information in an area by combing two elements into one space.  The graphs, maps, and sheet music examples in Graphic Design: The New Basics by Ellen Lupton are great examples of this ability to not only allow information to conceptually and visually combine to maximize space and so forth, these examples also show how the combination of these layers drastically improves their function and   readability.

Transparency is a major aid to the concept of layering.  It adds dimensionality without entirely obscuring and interrupting images.  Transparent images also suggest different meanings.  A faded image may be used to suggest a weakness or retreat.

 Inourassignment a few things happen with the layering of dot compositions and transparent semantic compositions.  Another meaning isn't created in the layering of our transparent and opaque pages, but instead the meaning of the word is enforced through the combination of the pages.  Our books also allow for the compositions to be viewed with or without the text semantics on the transparent pages.  In my book in particular there are three levels of layering and serendipity occurring.  As in my classmates books, the dot compositions and semantic compositions overlap to express one idea.  In my book a vector grid was printed as a background.  These vectors symbolize the dimensionality, graphing, and movement associated with ideas of physics.  The dot compositions will then be adhered to these pages with these grids in the background twisting in space and creating a dimensionality that spans from page to page.  These grids also suggest a greater sense of movement which is highly necessary in physics.  The flow of some of the grids will seem to carry some dots throughout the composition.  These grids are also on the backside of every page where no imagery occurs until the transparency page is flipped over and lies on top.  The words will then be backward, thus taking away from readability but the forms created in the semantic aspects will possibly interact with the moving grids.  Here are some pics of these grids.