Responses
I don't think I've seen a true litter box for dogs. You can train them to use a potty pad indoors though. I personally wouldn't recommend it, since some dogs don't really get the idea of limiting the potty area to just that one spot.
Gotta hand it to the artist for drawing the "heroine's" expressions like dog poop that has not been cleared from the litter box for months.
(Wait do dogs use litter boxes?)