Drawing; the basic unit & negative space

I went and Googled "Negative Space," in order to come up with some ways to help explain it to you, or maybe find some exercises other than the ones in Dr. Edward's book and I came across this person's blog. This is a great entry to help you really SEE examples of basic units. Look for the blue shapes.

The Spaces In-Between
Drawing Basics from mydesignselfstudy.com

Chapter 7 of Drawing on the Right Side of the Brain focuses on drawing the negative spaces of an image. Don’t draw the leaves. Instead draw only the edges of the spaces between the leaves. This takes the brain even farther away from its memorized symbols for images.

To aid with this exercise, Edwards introduces the “basic unit.” This basic unit is a shape, line, or unit within your scene against which every other line, shape, or unit is measured and compared.

Below is my first negative space drawing: I placed pheledendron leaves on the table and drew only the spaces between the leaves. I’ve highlighted one of the spaces in purple to help illustrate what I mean by “spaces”:

Below is my second negative space drawing: Here, I drew the negative spaces that exist around the positive forms of a chair. I chose the space in the middle (highlighted in purple) to be my basic unit. I compared all lines, shapes, and shape relationships against this basic unit. I didn’t quite get the drawing right. Drawing negative spaces is more difficult than it looks!