You can use two coins in a number of ways for example:
Heads= Dog
Tail= Cats
So if you got two tails then the family has two cats. But if you got 2 heads then you have two dogs. But if you got one head and one tail then they have one cat and one dog.
You could change the simulation by adding one more meaning for example:
Heads= Dog
Tail= Cats
Head+Tail= Frog.
