Both are ubiquitous, but one of them has to be more common than the other — even if we’ll never know which.

Think of a car, for instance. Most have four doors and four wheels, making them even. But then there are bicycles and motorcycles, which have two wheels and zero doors. Advantage, wheels! Houses, offices, and skyscrapers would appear to tilt things in the opposite direction — some of them have thousands of doors each. Then there’s the fact that wheels often have to be replaced, increasing their numbers substantially, whereas doors tend to last forever. This debate could last a while.