A closer look

If you have ever wondered why three identical pharmacies are built on the exact same intersection, blame Hotelling's model. If two ice cream stands start on opposite ends of a beach, one will eventually move toward the middle to capture more territory. The other will follow suit to reclaim their lost audience. Ultimately, they wind up sitting right next to each other in the exact center of the beach, annoying all the tourists who now have to walk further for a cone.