Thank you very much! Concerning my speech bubbles, I don't think I've seen any other comic where the speech bubble extends all they way into the characters' mouths, and I'm pretty satisfied with that little novelty of mine (if it is indeed novel). In regards to the way the characters interact with the speech bubbles, thought bubbles and panels, though, I has definitely been done before.
There's one classic Bizarro strip where a guy talks to his wife. He begins by saying something along the lines of: "I'm going to win the argument this time. You're not going to put words into my mouth". In front of him is his wife with a pen, filling in the rest of the speech bubble with something like: "You are completely right and I take everything back". I didn't consciously think of this strip when I first got the idea to
Squares and Bubbles, but it was almost certainly a subconscious influence.
Then there's
this comic by
Derek Yu (a brilliant artist and video game designer whom you should all check out), where the character interacts with his future self in a later panel. There's probably lots of other influences that I just can't think of at the moment.
