Normally I write these comic strip commentaries for a specific audience -- folks who casually read the funnies, but haven't really considered them as an art form. To that end, I'd like look at the Pastis/Watterson collaboration in a different way. While everyone was dazzled by Watterson's panels, there was a lot of brilliant cartooning going that no one seemed to have noticed.
The story arc starts innocently enough, laying the foundation (Pastis' lack of talent) that the week's strips will riff on. While "Libby" is an oblique reference to "Bill, " there is nothing in the appearance of the character to suggest anything vaguely related to Calvin and Hobbes. (click on images to enlarge)
In the first collaborative sequence, look carefully at Pastis' expression in the first and last panels. In the first, he's angry. It would be simple enough to keep that same look in the last panel without altering the joke. But instead of being mad at Libby's portrayal, he's stunned. It gives his line "I don't approve," a different context, making it a weak statement rather than a stern refusal.
The punchline of this sequence isn't just a humorous understatement -- it's a major issue in the comics world. The space allotted to comics continues to decrease. Many of the finely detailed drawings of older artists (from Windsor McKay to Frank Cho) would look cramped and muddied if reproduced in the smaller space that's now the norm.
The last collaborative sequence furthers the commentary on the state of comic strips with its punchline, too. (I've seen commentary claiming Betty and Veronica from "Archie" are depicted in the middle panel. Not so. There are three women -- a blonde, a brunette and a redhead. Having one of each natural hair color suggests the new and improved Stephen Pastis is appealing to all women.)
The story arc ends with a pointed reference to Calvin and Hobbes' final panel. Most readers seemed to have got the connection, but did they notice how Pastis set it up?
Watterson ended his comic strip with the characters set in an almost all-white backround. Here's the last panel below. It's easy to see that Pastis gave Libby the same sled and same clothes as Calvin. But look carefully at all of the strips that came before it. All of them have every panel encased in a border -- save for the final sequence. There, the first panel has no border. It's just open white space -- a reference to the wide-open white spaces of Watterson's original.