A nested context is like a matrioska doll. Each memeplex of ideas is contained within another, with the top layer reacting against your base personality. In the below example, Zen is the outermost layer. Not Zen Buddhism as such, but a derivative state of mind or rather, no-mind. It's a mental stance I assume when I'm preparing to do some mental work. So all the contextual feelings and concepts related to this Zen state fill my mind. And then, the next layer, I attempt to focus. Focusing your mind, for me, is a specific process, where I deliberately set aside most concious processes, in a very specific and identifiable mental action. Leaving only the next conceptual layer.
Which is Python. When I think of Python, I'm filled with concepts I've learned recently, code I admire, code I plan to write, and documentation I've read recently. I then turn to my Code, the second to last layer, and possibly the most specific. The code in front of me, completes my focusing of mind, and is where I do most of my work. But there is another layer, of Application, which is the larger purpose of that code. I tend to vacillitate between these two layers, but neither is far from my mind.
Now, obviously, this is not a rigid or literal construction of mind. If I were to be shocked, and lose concentration, I would not, for example, find myself in a higher level of the nested context. But rather this is a way of representing both the process of thought, and of the elements that make up concious processes. And it may be useful to you as a tool, for analysing the real source of thought. Now, I could expand the nested context, and include even more outward layers, all the way to basic processes of mind, but I limited my radius of attention in this case, in order to illustrate the concept. You may expand with this technique as far as convenience and your own knowledge of cognitive science allow.