Calvin Vs. The Hulk

I have recently begun re-reading the complete run of Calvin & Hobbes, and just finished the first collection.  It amazes me how strongly the strip started off - Bill Watterson had his character designs down from the outset, the cast of characters changed very little in appearance over the years.  Plus, Calvin's vivid imagination and perception of his stuffed tiger are firmly established within the first few strips.  No wonder it was such an instant hit with readers.