It isn't often that Mike Peters has cameos from other comic strips appear in Mother Goose and Grimm (see Love is Grimm for the most recent example). But when it does happen, it's always a special treat -- as in the March, 31, 2015 sequence. (click image to enlarge)
The reason it worked so well, I think, is because Peters' style is very close to Gary Brookins (the current artist for Shoe). So Shoe looks like Shoe -- not another artist's interpretation of Shoe. Peters' cameos may be rare, but they're always appreciated -- at least by this comics reader.