A few weeks ago, my family and I were wandering about in an unfamiliar part of the city where we live. We were getting hungry, so we started looking for a place to eat. We happened upon a block that had three restaurants in a row.
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2005/01/4723.gif?resize=300%2C220&ssl=1)
All three restaurants served types of food that we enjoy. Although it was early in the evening, one was already quite crowded. Another had a couple at one table near the window. The third appeared to have no customers.