In 1991, most characters had oval shaped faces and were much shorter and thinner, as well as big noses.
In 1993, the design clumped and it was wider. They also became much more different, as they seemed to have less caring and sensitivity.
In 1997, they changed even further. The characters were also less mean, and they got to it by 2001. There they expererienced more changes.
In 2006, the characters looked regular but continued to evolve in 2011. They seem to be somewhat different, but Chad's appearance was the most drastic. He is now a major character, and he is also playing a much larger role, a little more than in the old comics and books.
In 2017, the characters' foreheads became a lot bigger.
In 2019, Their eyes got bigger. Their old personality's started to very faintly come back into play. Dee Dee also became less of a drama queen by a lot. Yet, Artur has stayed the same through it all. Gina isn't in the comic as much and Nate......is still kind of the same.