Thinking this morning of those optical illusion drawings. Like the one that switches from a young Parisian women wearing a feathered hat to an old hag with a wart on her nose. Or the one that switches from two faces to a vase or chalice.
These are good illustrations of emptiness. What you see depends on your focus. Foreground and background are interchangeable, but reveal different pictures according to how you focus. The two aspects of the illusion are separate pictures but are also indivisible. The young woman cannot exist without the old. They are simultaneously a whole and individual parts. The parts that make up the hag are essential to the existence of the young woman and vice versa.
If I remember right, most people see the young woman first and after a time are able to see the hag. One feels a certain sense of wonder and delight when the transformation occurs. And after that, you can never look at that image without seeing both. I imagine this is the same sense of wonder one feels when a genuine realization of emptiness occurs.
We spend our whole lives looking at the foreground, never even realizing there is a background. If once we can shift our perspective enough to see the background, to bring it up front, our view of the world must change forever.
Now, take one step farther back and see yourself as the observer of the image. Another step in the exploration of emptiness. Because, really, the picture is meaningless without an observer. And the observer does not exist without something to observe. Thus, the two are separate but indivisible. Individual but united. Both one and not one. Interdependent. Empty.
Here, the observer (me) is the foreground. The picture is the background. All the activity is going on in me, the foreground, and being projected onto the background. Like looking out the window of my eyes and seeing the world pass by like a film on a screen. What if the screen suddenly comes to the fore? How different things would look!