In exercise 2.6 we are to compose the out-of-focus part of the frame instead of using it merely to block out the background. With this comes the main focus on subject foreground.
As the images show, the main part of the photo is indeed the large surface area of the photo.
Unedited sequence:
Edited for use images (Selected)
As with the previous exercise on changing depth of field, here also my thinking is that the subject foreground gives rise to defining the image in its entirety. The subject contextualises the photo when you cannot quite distinguish the object that is out of focus.
I explored the like with like images to see if it was easier to interpret the image when the background is out of focus and the foreground subject is sharp. Below is an example of that.
OCA log level 1 Photography 