Evy, if there's one thing I've learned while reading Mary Worth, it is to Never Ask Why. I mean, "Why are you sharing a deck chair?" "Why is it so loosely weaved?" "Why is Ed crammed into the armrest?" "Why does your left knee look like your right knee, or vice versa?" "Why doesn't Ed have nipples?" This is just one panel. No, Evy, never ask why. Just accept it and move on.
However, if you want to ask "who" and "how," please read this charming little profile on Giella and Moy.