You're probably wondering why on earth I'm posting PowerPuff Girls artwork, there is an explanation, I assure you. I've been using their model sheets along with a loose script that I wrote in my storyboarding class to introduce the mechanics of animation storyboarding. While I have students who are animation majors, I also have a lot of students who aren't and the PowerPuff Girls are simple enough that they don't scare non-cartoonists off. These drawings were just quick demos on constructing the forms by drawing them through for storyboards. I don't have them worry about being "On-Model" too much but rather to concentrate on hook-ups key framing and visual logic.
I always round these characters out a lot more than the model sheets by making their bodies these cone forms and not triangles. I understand the reason for the flatness under the production constraints of the show...but I'm not beholden to that.