- 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.