I has been such a cute project to work on, and it was a great pleasure and experience to be working with this client too. In English the game is also known as "Old Maid" and in the Netherlands it used to be called "Zwarte Piet." The game contains playing cards with pairs of dogs and cats.
This is how it works: The cards are equally distributed to each player. The moment a player makes a pair in their hands, they discard them immediately onto the table. Each player is trying to get rid of his or her cards as fast as possible. In the end there is only one player left, holding the unmatched card (the Old Maid). That player has lost the game and is the "old maid."
Of course you can also turn the rules around, making the one who ends up with the odd card the winner. The whole experience of the game will change that way.
I am a cat lover, rather than a dog lover. But if I would ever have a dog I think it would be a long curly haired dachshund. I've always loved these little pretty doggies. They are my favorite. A childhood friend of mine used to have two (one of them long haired), and I was crazy about them. I really couldn't leave this doggy out of the game, so the dachshund became part of the card deck, and I gave her a pencil and sketchbook to draw butterflies with.
Later when the art director was naming the animals, she asked me if she had permission to name the dachshund after me, because she thought it would suit the character. I felt very flattered and agreed. So now the dachshund is called Miriam.