Your analogy makes no sense at all. I guess you don't mean the same "blank", but even then, what relationship are you trying to convey?

Does blank represent the same thing in both comparisons?

Analogies provide three out of the four parts, not two. As written, "Mammal is to mammal as furniture is to furniture" is correct but foolish.

Probably practice in hyper- hyponyms... cat is to mammal as chair is to furniture.

"Foot' is to mammal as leg" is to furniture" seems possible; mammals stand on their feet and furniture often has legs to stand on.

How about "six is to mammal as nine is to furniture"?

@LPH nice find: not all mammals have feet either.

I'd put count / noncount, but still claim that 'furnitures' exists.

I like Greybeard's comment, was going to write it but with dog instead of cat; possibly 'feline' would be more general, just as there are several types of chairs.

I'd vote to re-open if I could.

This is a fun way to procrastinate! lammam:mammal :: erutinruf:furniture -- animal:mammal :: household good:furniture -- flying squirrel:mammal :: flying carpet:furniture -- horse:mammal :: rolling chair:furniture -- sloth:mammal :: la-z-boy:furniture -- emlős:mammal :: bútor:furniture -- Earth:mammal :: Earth:furniture

Milk is to mammal as a joiners paycheck is to furniture. (you can even say that the paycheck is produced by the furniture, when it's sold)

Human is to mammal as throne is to furniture, if we take an old fashioned view of both evolution and social hierarchy.

Fur is to mammal as upholstery is to furniture?

I could make a case for "fish is to mammal as appliances is to furniture"

@DJClayworth I wonder what the common ancestor of appliances and furniture is. The milking stool? (ancestor of the easy chair and the refrigerator)

The common ancestor is "things that go in your house". But the point is just to illustrate that there are huge numbers of potential answers to this and it's a bad question.