Owner Mallory Slate says the two stores are "carbon copies," and convenience is "absolutely" the only factor that would lead a consumer to choose one store over the other.

Slate explains that the Church Street store, which first opened in 1975 and moved to its current location in 1991, was necessary because the original store, at 1288 Mass. Ave., had run out of space.

"We were maxed out," he says.

Though the stores have few major variations, the difference is in the details.

For example, just inside the door of the Church Street store is a large display of hand-painted wooden boxes in bright colors--a display absent from the Mass. Ave. store.

Slate explains that because the two stores have different merchandising managers, they might carry some different products, but the bulk of the products and the basic lines of products carried are uniform.

"Like people, the stores have personality," he says.

As with Starbucks, the different neighborhoods within the Square have helped to shape this personality.

Slate says the Mass. Ave. store is busiest in September and January with the spiralbound notebook business.

The Church Street location, he says, experiences a larger rush around the holiday season, drawing the gift-shopping Crate & Barrel crowd.

And apparently this crowd was lying in wait for Slate's goods.

"When we opened the second store, we doubled our business right away," Slate says.

In general, though, he says the stores see equal amounts of business.

CVS vs. CVS

But perhaps the most prominent example of a double location is CVS. The two stores are separated by barely a block. A customer can stand at the door of one CVS and see the other.