I haven't gotten a newspaper at home in years, but every now and then my father sends me clippings of comics or articles. The comic that he seems to send the most is Pearls Before Swine which has a periodic flair for formalism.
In the last set that he sent, the characters do a fair amount of walking on the borders of the panels (Here, Here, and Here):
"Awareness" of panel borders by characters within them is nothing new, but doing so it reveals that there are two levels of representations in this visual language of comics. There is a "Representational Plane" (RP) that the content exists in, and a "Framing Plane" (FP) that holds things like panel borders and balloons/bubbles/text boxes. Usually, the Framing Plane just lies "outside" the RP, but instances like these collapse the layers together. (see linked essay below for illustrations of this)
Another hint that these two layers exist comes from the fact that text carriers can become panels, as I discussed in my article on "Loopy Framing":
This commonality between their forms — that they both encapsulate information, both are not part of the image matter but can be interacted with in a "meta" way — go towards their being two aspects of a singular plane of Framing.
Note: For those more interested, I discuss this more extensively in my paper Interactions and Interfaces.