The second exercise works with the very same previous images but now we are to imagine the objects are holes. Think of them as nothing at all. Another spin is to imagine "looking at a piece of solid white wood full of empty black holes".
Another quote from Notan, The Dark-Light Principle of Design:
"The visual exchange--the perception of a shift from things to no-things, from no-things to things--is a characteristic of Notan."
So in the first exercise, the black blobs were objects. It was all about them. Background wan't really a consideration. With today's exercise, the white is the object and the blobs don't exist.
One final quote:
"Do not hurry with this exercise. Like plants and trees, we create at the same rate that we grow--very slowly. Though we are always trying to force ourselves to rush at the rate of machines, our pace n this work cannot be rushed."
Hopefully not in too much of a hurry, we'll wrap up the Asymmetrical Balance exercises. I'll bet you know where this is going... :-)