Exploring perception and the overlay of thoughts can yield a great variety of insights, and one of the most effective ways of exploring this that I have found so far is the choiceless awareness practice, differentiating the sense fields and thoughts through labeling.
The practice helps me see how thoughts are overlaid on perception to create a sense of extent and space, continuity and time, a center and periphery, inside and outside (not in my case, but I see how it can happen), and related ones such as seeing and seen, seer and seen, a doer, a chooser, and so on.
The practice also helps me in seeing how these thoughts come in different forms.
In general, I notice how thoughts mimic the sense fields. There are image thoughts, sense thoughts, sound thoughts, smell thoughts, and taste thoughts. Thoughts create a whole imaginary sensory world, and make up its own sense field.
Then there are the discursive thoughts, the ordinary self-talk (“I wonder how the presentation tonight at Luna will be. At least the beer will be good.”)
There are also image thoughts overlaid on perception. One type of these are interpretations and suggestions for what the perceptions are, such as in image of a car put on top of a particular sound. Others are overlaid on perception and create a sense of extent, continuity, center and periphery, and so on.
This noticing is in real time, as it happens, during more formal practice sessions and also daily life.
And this differentiation of the sense fields, and particularly thought, also helps me see how gestalts are formed through the combination of sense fields.
For instance, what may appear as an emotion is just a sensation and a story about this sensation. And what appears as a separate self emerges from the combination of perceptions in a particular area of space (bodily sensations, and sights and sounds from this human self) and image thoughts of a separate self. The image thoughts of extent (space), continuity (time), center and periphery, seeing and seen, seer and seen, doer, and so on, helps flesh out this particular gestalt, making it appear very real if not see directly as this conglomerate of components.